Everything you need to know about PL SQL

PL SQL Tutorial

PL/SQL is the Oracle Company’s procedural extension for SQL, i.e. Procedural Language for Structured Question Language (SQL) and the Oracle relational database. It was developed within the late 1980s. PL/SQL is on the market in Oracle Database, TimesTen in-memory database, and IBM DB 2. PL/SQL is a block-structured language. The written applications in PL/SQL are logical blocks that may include any variety of nested sub-blocks.

PL/SQL ensures logical processing of SQL statements by enhancing the info’s security, portability, and robustness. PL/SQL instructs the compiler ‘what needs to be executed by SQL and ‘the way it needs to be executed by its procedural method. Like different database languages, it offers management to the programmers by making use of loops, situations, and object-oriented ideas.

On this PL SQL Tutorial, we’ll see:

  1. Traits of PL/SQL
  2. Benefits and Disadvantages of PL/SQL
  3. Structure of PL/SQL
  4. Distinction Between SQL and PL/SQL
  5. PL/SQL Set up 
  6. PL/SQL program block-structure
  7. Fundamental Syntax of PL/SQL  
  8. PL/SQL Datatypes
  9. PL/SQL Variables
  10. PL/SQL Constants and Literals
  11. PL/SQL Operators

Traits of PL/SQL:

  • PL/SQL is seamlessly built-in with SQL.
  • It gives an intensive characteristic of error checking.
  • It additionally gives quite a few varieties of knowledge varieties.
  • It gives programmers to pick programming constructions.
  • It’s block-structured programming that gives help to features and procedures.
  • It helps object-oriented programming ideas and options.
  • It helps the occasion of net purposes and server web page growth.

Benefits of PL/SQL:

  • SQL is that the standard database language, and PL/SQL is strongly built-in with SQL. PL/SQL helps each static and dynamic SQL.
  • In Static SQL DML operations and transaction, management is supported from PL/SQL block. In Dynamic SQL, embedded DDL statements are allowed in PL/SQL blocks.
  • It sends a complete block of statements to the database on only one event. This helps to scale back community visitors and likewise offers excessive efficiency for the purposes.
  • PL/SQL offers excessive productiveness efficiency to programmers as a result of it might question, rework, and replace knowledge throughout a database.
  • PL/SQL reduces time consumption on design and debugging by robust options, like exception dealing with, encapsulation, knowledge hiding, and object-oriented knowledge varieties.
  • The purposes written in PL/SQL are extremely moveable.
  • PL/SQL offers a high-security stage.
  • PL/SQL offers entry to predefined SQL packages.

Disadvantages of PL/SQL:

  • Procedures which are saved in PL/SQL use excessive reminiscence areas.
  • These saved procedures lack performance debugging. 
  • Any change happening within the major database wants a change within the presentation layer additionally.
  • It doesn’t separate the roles of back-end developer and front-end developer.
  • It is extremely troublesome to separate HTML growth from PL/SQL growth.

Additionally Learn: SQL Tutorial for Inexperienced persons

The Structure of PL/SQL:

PL/SQL block:

PL/SQL block is the half the place precise PL/SQL code is current. This half incorporates totally different sections to divide the code logically, just like the declaration part for declaring objective, execution part for processing, exception dealing with part for dealing with errors. It additionally consists of the SQL instruction that’s used to work together with the database server. All of the PL/SQL models are managed as PL/SQL blocks, and that is the stage the place the structure begins serving as a major enter.

Following are some various kinds of PL/SQL models:

  • Nameless Block
  • Operate
  • Library
  • Process
  • Bundle Physique
  • Bundle Specification
  • Set off
  • Kind
  • Kind Physique

PL/SQL Engine:

PL/SQL engine is the part the place precise processing of the Pl/SQL codes takes place. PL/SQL engine divides PL/SQL models and SQL half within the enter. The divided PL/SQL models will probably be managed by the PL/SQL engine itself. The SQL half, which was separated by the PL/SQL engine, will probably be despatched to the database server, the place the precise interplay with the database happens. It may be put in in each the database server and within the software server.

Database Server:

That is an important a part of the PL/SQL unit, which shops the info. From the PL/SQL unit, the PL/SQL engine makes use of SQL to work together with the database server. It consists of an SQL executor which parses the enter SQL statements and executes the identical.

Distinction between SQL and PL/SQL:

SQL PL/SQL
SQL is Structured Question Language, a single line assertion to carry out DML and DDL operations. PL/SQL is a block-structure of codes which are used to write down the complete program blocks, process, operate, and many others.
It’s a declarative assertion that defines what needs to be executed. PL/SQL is a block of code that incorporates a process that defines how issues needs to be executed.
It executes as a single assertion at a time. It executes as a complete code block at a time.
It’s used primarily for knowledge manipulation. PL/SQL is especially used to develop an software.
It interacts with a database server It doesn’t work together with the database server.
SQL can’t include PL/SQL code inside it. PL/SQL is an extension of SQL in order that it incorporates SQL inside it.

PL/SQL Set up:

PL/SQL shouldn’t be an impartial programming language; it’s a software inside the Oracle programming. To work with PL/SQL, we’ll use SQL*Plus. SQL* Plus is an interactive software that permits us to write down SQL and PL/SQL instructions or statements on the command immediate. After offering the instructions to the immediate, the instructions are then despatched to the database for processing. As soon as the database processes the instructions, the outcomes are displayed on the display screen.

To execute PL/SQL applications, we should always have the Oracle RDBMS Server put in in our programs chargeable for the execution of the SQL instructions.

Initially, we’re going to obtain Oracle Database 11g Launch 2 on Microsoft Home windows (x64) from Oracle official web site. We are going to obtain the 32-bit or the 64-bit model of the set up as per our working system requirement. We are able to additionally observe related steps for the Linux working system.

After downloading Oracle Database 11gR2 Specific Version for Home windows x64 zip file unzip or extract the recordsdata contained in the zip file.

1.JPG

Following are the steps to put in and Launch Oracle database efficiently.

  1. Click on on the setup and the set up wizard window will begin getting ready it for set up. That is the primary display screen which we’ll see. Click on on the subsequent button.12.JPG2.JPG
  2. Settle for the license settlement and click on on the subsequent button.3.JPG
  3. Now select the vacation spot location for the file set up. And click on on the subsequent button.4.JPG
  4. Set the database password and click on on the subsequent button. 5.JPG
  5. The ultimate set up window seems on the display screen, click on on set up.6.JPG
  6. Oracle set up will set up the required configuration recordsdata. It will take a while.7.JPG 
  7. The set up setup configures the database.8.JPG
  8. After set up, we’ll see the next window. Click on on the end button.9.JPG
  9. Now, we’ll confirm our set up. On the command immediate, write the next command and press enter to confirm set up on Home windows.

10.JPG

The set up is efficiently accomplished.

Textual content Editor:

It’s at all times advisable to make use of the command recordsdata whereas working the applications from command immediate. There are numerous textual content editors to create the command recordsdata and run them simply:

  • We are able to sort code in textual content editors like Notepad, Notepad++, EditPlus, UltraEdit, and many others.
  • Save this program file with the extension of .sql within the house listing.
  • Now, on the SQL*Plus command immediate sort file_name and press enter to execute your program.

We are able to additionally straight execute applications with out creating applications. Simply write the code on the SQL command immediate and press enter key and this system will probably be executed.

PL/SQL Program Construction: 

The nameless code block construction has three important sections which are the declaration, execution, and exception dealing with. In PL/SQL, solely the execution part is obligatory, and the opposite sections are optionally available. 

Declaration Part

Within the declaration part, we outline knowledge varieties, constructions, and variables. We declare variables on this part by giving these names, knowledge varieties, and preliminary values.

Execution Part

The execution part is an important and required part in a block construction, and it should include not less than one assertion. The execution part is the place the place we put the execution code or enterprise logic code. We use each procedural and SQL statements on this part.

Exception Dealing with

The exception part is the place the place we put the code to deal with exceptions. We are able to deal with and catch exceptions on this part.

Fundamental Syntax of PL/SQL:

The PL/SQL nameless code block construction has three important sections which are the declaration, execution, and exception dealing with:

Declare

This part begins with the key phrase DECLARE. Within the declaration part, we outline knowledge varieties, constructions, and variables. The Declaration part is an optionally available part.

Executable Instructions

The part is enclosed between the 2 key phrases, BEGIN and END, and it’s a compulsory part. It incorporates all of the executable PL/SQL statements of this system. This part ought to include not less than one executable assertion of code, which will also be a NULL command to level out that nothing goes to be executed.

Exception Dealing with

This part begins with the key phrase EXCEPTION. This part is optionally available and incorporates exceptions that deal with errors if current in this system.

Each PL/SQL assertion ends with a semicolon (;). PL/SQL blocks are nested inside different 

PL/SQL blocks utilizing BEGIN and END key phrases. Following is the first construction of a PL/SQL block-structure: 

Instance:

DECLARE

	BEGIN

		EXCEPTION

	END;


First ‘Whats up World’ program:

BEGIN
	dbms_output.put_line ('Whats up World');
	END;
	/

The END; line indicators the highest of the PL/SQL block i.e. execution begins from high. When the above code is executed on the SQL command immediate, it produces the next consequence −

Whats up World

The PL/SQL Identifiers:

PL/SQL identifiers are constants, variables, exceptions, procedures, cursors, and reserved phrases that can not be used for different applications. The identifiers include a letter optionally adopted by extra letters, numerals, symbols, underscores, and quantity indicators and needs to be within the size of 30 characters.

Identifiers are usually not case-sensitive. So we use integer or INTEGER to signify a numeric worth. Notice that we can’t use a reserved key phrase as an identifier.

In programming languages, feedback are the statements that specify this system to the reader, which will probably be included inside the code. All programming languages enable some type of feedback inside the code block. The PL/SQL additionally helps single-line and multi-line feedback. All of the directions contained in the remark are ignored by the PL/SQL compiler. The one-line feedback in PL/SQL begin with a delimiter — (double hyphen), and multi-line feedback are enclosed inside /* and */.

DECLARE
	-- variable declaration
	msg varchar2(20):= 'Whats up, World!';
	BEGIN
	/*
	* PL/SQL executable statements
	*/
	dbms_output.put_line (msg);
	END;
	/

Following is the output of above code −

Whats up World

PL/SQL Datatypes:

Each Information Kind is related to some specific sort of storage format and vary constraints in programming languages. It defines how the info needs to be saved, dealt with, and handled by Oracle throughout the knowledge storage and processing. The important thing distinction between PL/SQL and SQL knowledge varieties are, the PL/SQL datatypes are utilized within the PL/SQL code blocks, however SQL knowledge varieties are restricted solely to the tables and columns.

Sorts of Information Sorts:

Scalar: A Single worth with no inside elements, equivalent to a NUMBER, DATE, or BOOLEAN comes below Scalar knowledge varieties.

Composite: The Information gadgets which have inside elements and are sometimes accessed individually. Instance assortment and information.

Reference: These knowledge varieties are tips to different knowledge gadgets current in reminiscence.

Giant Object (LOB): The tips to massive objects or recordsdata which are saved individually from different knowledge gadgets, like textual content, graphic photos, video clips, and sound waveforms come below massive objects.

PL/SQL Scalar Information Sorts and Subtypes 

Datatype Description
Numeric Numeric values on which arithmetic or mathematical operations may be carried out.
Character These are Alphanumeric values that signify single characters or strings of characters.
Boolean Boolean knowledge sort represents the Logical values on which logical operations may be carried out.
Datetime This knowledge varieties shops the Dates and instances values.

In PL/SQL, some knowledge varieties have subtypes of knowledge varieties. For instance, the datatype NUMBER has a subtype INTEGER, BINARY_INTEGER, BINARY_FLOAT, and many others. We are able to use these subtypes in PL/SQL applications to make the info varieties appropriate with knowledge varieties utilized in different applications whereas embedding the PL/SQL code in different applications.

PL/SQL Numeric Information Sorts and Subtypes

Information Sorts Description
PLS_INTEGER It’s a signed integer within the vary of -2,147,483,648 by 2,147,483,647, represented in 32 bits reminiscence.
BINARY_INTEGER It’s a signed integer within the vary of -2,147,483,648 by 2,147,483,647, represented in 32 bits reminiscence.
BINARY_FLOAT It’s a single-precision IEEE 754-format floating-point quantity.
BINARY_DOUBLE It’s a double-precision IEEE 754-format floating-point quantity
NUMBER(prec, scale) This datatype is a Mounted-point or floating-point quantity with fastened worth within the vary of 1E-130 to (not inclusive) 1.0E126. A NUMBER knowledge sort variable also can signify zero(zero).
DEC(prec, scale) It’s an ANSI specified fixed-point sort knowledge sort with most precision of 38 decimal locations.
DECIMAL(prec, scale) It’s IBM specified fixed-point sort datatype with most precision of 38 decimal locations.
DOUBLE PRECISION It’s an ANSI specified floating-point sort with most precision of 126 binary digits i.e. roughly 38 decimal locations.
FLOAT That is an ANSI and IBM particular floating-point sort with most precision of 126 binary digits i.e. roughly 38 decimal locations.
INT It’s an ANSI particular integer sort with most precision of 38 decimal locations
INTEGER That is an ANSI and IBM particular integer sort with most precision of 38 decimal locations
SMALLINT That is an ANSI and IBM particular integer sort with most precision of 38 decimal locations.
REAL It’s a Floating-point sort with most precision of 63 binary digits i.e. roughly 18 decimal locations.

Following are the legitimate declarations of subtype of NUMBER datatype:

DECLARE —declare key phrase used for declaration

num1 INTEGER; — num1 is a legitimate variable identify for storing integer sort worth

num2 REAL; — num2 is a legitimate variable identify for storing actual sort worth

num3 DOUBLE PRECISION; — num3 is a legitimate variable identify for storing double precision sort worth:

BEGIN
null;
END;
/

 PL/SQL Character Information Sorts and Subtypes

Information Sorts Description
CHAR It is a fixed-length character string knowledge sort with a most measurement of 32,767 bytes.
VARCHAR2 It is a variable-length character string knowledge sort with a most measurement of 32,767 bytes.
NCHAR It is a fixed-length nationwide character string knowledge sort with a most measurement of 32,767 bytes.
NVARCHAR2 It is a variable-length nationwide character string knowledge sort with a most measurement of 32,767 bytes.
LONG It is a variable-length character string knowledge sort with a most measurement of 32,760 bytes.
ROWID It is a bodily row identifier. This knowledge sort shops the handle of a row in an odd desk.
UROWID That is an Common row identifier datatype (bodily, logical, or overseas row identifier).

PL/SQL Boolean Information Sorts

The BOOLEAN datatype shops logical values which are used to carry out logical operations. The logical values equivalent to TRUE and FALSE and the worth NULL comes below BOOLEAN datatype.

SQL has no datatype like BOOLEAN. Due to this fact, Boolean values can’t be utilized in −

  • SQL statements
  • Constructed-in SQL features 
  • PL/SQL features invoked from SQL statements

PL/SQL Datetime and Interval Sorts

The DATETIME datatype is used to retailer fixed-length Datetime values, which embody the time of day in seconds since midnight. The default date format is perhaps ‘DD-MON-YY’, which features a two-digit quantity for the day of the month, an abbreviation of the month identify, and the final two-digit quantity for the yr. For instance, 07-APR-21. Following is the legitimate values for every area −

Datetime Values Interval Values
    YEAR -4712 to 9999 (excluding yr zero) Have to be a nonzero integeri.e. 9999-4712=5287 years interval.
  MONTH 01 to 12 zero to 11
  DAY 01 to 31 (based mostly on the values of MONTH and YEAR) Have to be a nonzero integer
   HOUR 00 to 23 zero to 23
  MINUTE 00 to 59 zero to 59
  SECOND 00 to 59.9 zero to 59.9
   TIMEZONE_HOUR 12 to 14  Not relevant
TIMEZONE_MINUTE 00 to 59 Not relevant

 PL/SQL Giant Object (LOB) Information Sorts:

Giant Object (LOB) datatypes are referred to massive knowledge gadgets like textual content recordsdata, graphical photos, video clips, and sound waveforms. Following are some PL/SQL LOB knowledge varieties −

Datatype Description
 BFILE This datatype is used to retailer massive binary objects in working system recordsdata outdoors the database. It’s system-dependent and can’t exceed Four gigabytes (GB).
  BLOB This datatype is used to retailer massive binary objects within the database and within the vary of Eight to 128 terabytes (TB).
 CLOB This datatype is used to retailer massive blocks of character knowledge within the database within the vary of Eight to 128 TB.
   NCLOB This datatype is used to retailer massive blocks of NCHAR knowledge within the database within the vary of Eight to 128 TB.

NULLs in PL/SQL:

PL/SQL NULL values signify lacking or unknown knowledge and that they aren’t an integer, a character, or the opposite particular knowledge sort. Notice that NULL isn’t an equal as an empty knowledge string or the null character worth ‘’. A null is usually assigned however it might’t be equated with something, together with itself.

PL/SQL Variables:

PL/SQL programming language permits to outline varied kinds of variables, like date time knowledge varieties, information, collections, and many others. which we’ll cowl in subsequent chapters

Variable Declaration in PL/SQL:

The variables needs to be declared within the declaration part of the PL/SQL code block construction. It will also be declared in a package deal as a world variable. When a variable is asserted, PL/SQL allocates reminiscence to the variable and shops the specified sort worth and the storage location is recognized by the variable identify.

The syntax for declaring a variable is −

variable_name [CONSTANT] datatype [NOT NULL] [:= | DEFAULT initial_value] 

The place, variable_name is a legitimate variable identifier in PL/SQL, datatype should be a legitimate PL/SQL knowledge sort. Some legitimate variable declarations are given beneath:

age quantity(Three); 

pi CONSTANT double precision := Three.1415; 

identify varchar2(25); 

handle varchar2(100);

Within the instance the scale, scale or precision restrict with the info sort can also be offered, it’s known as constrained declaration. Constrained declarations occupy much less reminiscence than unconstrained declarations. For instance −

Initializing Variables in PL/SQL:

Variable declaration in PL/SQL assigns it a default worth NULL. If we wish to initialize a variable with a not NULL worth, we will do that throughout the variable declaration, utilizing of the next key phrases −

  • The DEFAULT key phrase
  • The task operator(=)

For instance −

counter binary_integer := zero; 

greetings varchar2(20) DEFAULT 'Have a Good Day';

We are able to additionally specify that a variable mustn’t have a NULL worth utilizing the NOT NULL constraint. If we use the NOT NULL constraint, we should assign an preliminary worth to that variable. It’s a good apply to initialize variables correctly.

Following is an instance of varied forms of variables:

DECLARE
	a integer :=10;
	b integer :=20;
	c integer;
	d actual;
BEGIN
	c := a+b;
	dbms_ouput.put_line('Worth of variable c:' ||c);
	d :=45.5/Eight.Three;
	dbms_ouput.put_line('Worth of variable d:' ||d);
END;
/

Following is the output of above code:

Worth of c: 30 

Worth of f: 23.333333333333333333  

Variable Scope in PL/SQL:

In PL/SQL, we will carry out nesting of blocks, i.e., every program block might include one other inside block. If a variable is asserted inside an inside block it isn’t accessed by the outer block. And, if a variable is asserted and accessible to an outer block, it can’t be accessed by all nested inside blocks. There are two forms of variable scope −

  • Native variables − the variables declared inside an inside block and isn’t accessible to outer blocks.
  • International variables − the variables declared within the outermost block or in a package deal as international variable.

Following is the instance of Native and International variables:

DECLARE
	p quantity :=20;     --global variables
	q quantity :=30;
BEGIN
	dbms_output.put_line('International variable p:' || p);
	dbms_output.put_line('International variable q:' || q);
	DECLARE
	p quantity :=102;    --local variables
	q quantity :=130;
	BEGIN
	dbms_output.put_line('Native variable p:' || p);
	dbms_output.put_line('Native  variable q:' || q);
	END;
END;
/

Following would be the output of above code:

International variable p: 20

International variable q: 30 

Native variable p: 120 

Native variable q: 130   

PL/SQL Constants and Literals:

A relentless holds a worth that, when declared, doesn’t change inside the program. A relentless declaration specifies its identify, knowledge sort, and worth and likewise allocates storage for it within the reminiscence. The declaration additionally imposes the NOT NULL constraint. 

A relentless is asserted utilizing the CONSTANT key phrase. An preliminary worth is assigned to it which isn’t allowed to be modified. For instance −

Program to seek out circumference and space of circle:

PI CONSTANT NUMBER := Three.141592654; 
DECLARE 
   pi fixed quantity := Three.141592654; 
   radius quantity(5,2);  
   dia quantity(5,2);  
   circumference quantity(7, 2); 
   space quantity (10, 2); 
BEGIN   
   radius := 9.5;  
   dia := radius * 2;  
   circumference := 2.zero * pi * radius; 
   space := pi * radius * radius; 
   dbms_output.put_line('Radius: ' || radius); 
   dbms_output.put_line('Diameter: ' || dia); 
   dbms_output.put_line('Circumference: ' || circumference); 
   dbms_output.put_line('Space: ' || space); 
END;
/

Following would be the results of the above code:

Radius: 9.5 

Diameter: 19 

Circumference: 59.69 

Space: 283.53  

PL/SQL Literals:

A literal is a specific numeric, character, string, or Boolean worth which isn’t represented by an identifier. For instance, TRUE, FALSE, 2021, NULL, ‘Programming’ are all literals. PL/SQL literals are case-sensitive. PL/SQL has the next forms of literals:

  • Character Literals: – Instance ‘A’ ‘%’ ‘9’ ‘ ‘ ‘z’ ‘(‘.
  • Numeric Literals: – Instance zero40 68 -15 zero +367, 6.667 zero.zero -12.7 Three.14159 +8900.00, 4E5 1.0E-Eight Three.13159e0 -1E38 -Four.5e-Three.
  • String Literals: – Instance ‘Whats up, world!’, ‘Procedural Language for SQL’, ’07-APR-21′.
  • BOOLEAN Literals: – Instance TRUE, FALSE, and NULL.
  • Date and Time Literals: – Instance DATE ‘1978-12-25’; TIMESTAMP ‘2020-10-29 12:01:01’;

Following is the instance of  embedding the only quotes in a string literal, place two single quotes subsequent to one another as proven within the following program −

DECLARE 
   msg  varchar2(30):= 'That is  ebook to review programming!'; 
BEGIN 
   dbms_output.put_line(msg); 
END; 
/  

Following would be the  results of above code:

That’s an excellent ebook to review programming!  

PL/SQL Operators:

An operator is a logo that tells the compiler to carry out some particular mathematical or logical operations. PL/SQL language consists of  wealthy in built-in operators. Following forms of operators:

  • Arithmetic Operators
  • Relational Operators
  • Comparability Operators
  • Logical Operators
  • String operators

Arithmetic Operators:

Following are arithmetic operators supported by PL/SQL. Let’s perceive this with an instance. Suppose we’ve got two variables a and b with the values 2 and 40 respectively. We are going to carry out the arithmetic operation on each the variables.

Operator Identify Description Instance
+    Addition operator This operator is used so as to add two numbers. a + b    i.e.2 + 40 = 42
–    Subtraction operator This operator is used for subtraction of two numbers. b – a      i.e.40 – 2 = 38
*   Multiplication operator This operator is used to carry out multiplication operations between two numbers. a * b   i.e.2 * 40 = 80
/   Division operator This operator is used to divide two numbers. Numerator/Denominator b / a    i.e. 40 / 2 =   20
** Exponential operator This operator is used to lift energy to any quantity. b**a  i.e.40**2 = 1600

Relational Operators:

Relational operators are used to carry out comparability between two expressions or values and supply a Boolean worth consequently. Let’s perceive this with an instance. Suppose we’ve got two variables a and b with the values 2 and 40 respectively. 

Operators Identify Description Instance
=equals to This operator is used to examine if the values of two operands (right here, a and b) are equal or not, if sure then situation turns into true and returns additionally true. a = b shouldn’t be true.
!=< >~=not equals to These all three operators carry out the identical sort of process. They examine whether or not the values of operands right here a and b are equal or not, if values are usually not equal then situation turns into true and returns additionally true. a != b is true.
>better than This operator is used to examine whether or not the worth of operand a is larger than the worth of operand b. If a is larger than b then situation turns into true and returns additionally true. a > b shouldn’t be true.
<lower than This operator is used to examine whether or not the worth of operand a is lower than the worth of operand b. If a is lower than b then situation turns into true and returns additionally true. a < b  is true.
>=better equal to This operator is used to examine whether or not the worth of operand a is larger than equal to the worth of operand b. If a is larger than equal to b then situation turns into true and returns additionally true. a >= b shouldn’t be true.
<=lower than equal to This operator is used to examine whether or not the worth of operand a is lower than equal to the worth of operand b. If a is lower than equal to b then situation turns into true and returns additionally true. a <= b is true

Comparability Operators:

Comparability operators are used for evaluating one expression to a unique one. The consequence after utilizing these operators are at all times be TRUE, FALSE or NULL. Comparability operator is especially in SQL statements.

Operator Identify Description
LIKE The LIKE operator is used to check and examine worth to a sample and returns TRUE if the worth matches in any other case returns FALSE if it doesn’t.
BETWEEN The BETWEEN operator is used to examine whether or not the worth of operand lies in BETWEEN the vary or not.
IN The IN operator is used to examine whether or not the set is current or not. 
IS NULL This operator is used to examine for any null or not null worth within the desk. The IS NULL operator returns the BOOLEAN worth TRUE if its operand is NULL or FALSE if it isn’t NULL. 

Logical Operators:

Logical operators are used to carry out comparability between two expressions or values and supply a Boolean worth consequently. Let’s perceive this with an instance. Suppose we’ve got two variables a and b with the values 2 and 40 respectively. 

Operator identify Description Instance
AND That is logical AND operator. It lies between two situations to examine each the situations on the identical time. The consequence turns into true when each the situations are glad in any other case returns false. a =b AND a > b is fake.a =b or AND a < b is fake.a !=b AND a < b is true.(each the situations are usually not  glad).
OR That is logical or operator. It lies between two situations to examine each the situations on the identical time. The consequence turns into true when not less than one situation is glad and if each the situations are usually not glad then returns false. a =b OR a > b is fake.a =b OR a < b is true.a !=b OR a < b is true.(each the situations are usually not  glad).
NOT A NOT operator performs logical negation on situations. In different phrases, if the situation is true, then the output will probably be false. Equally, a false situation ends in a real output.  NOT a and b is true.

This brings us to the top of the PL SQL Tutorial. We hope that you’re now higher geared up with the ideas.

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