PL/SQL If-then statements

if-thenStatements are the IF simplest form of a control statement and are often used to make decisions and change the control flow of program execution.

IFA statement associates a condition with THEN a keyword and END IF a sequence of statements that it contains. If the condition is TRUE , the statement will be executed, and if the condition is FALSE or NULL , the IF statement block will not take any action.

Grammar

IF-THENThe syntax of the statement is-

IF condition THEN     S; END IF;

Here, condition a Boolean or relational condition S is a simple or compound statement. Here is IF-THEN An example of a statement-

IF (a <= 20) THEN   c:= c+1;END IF;

If the Boolean expression condition evaluates to true , the if code block in the statement is executed. If the Boolean expression evaluates to false , the if first set of code after the end of the statement (after the end) is if executed.

Flow chart

Example-1

Let's take a look at an example to understand the above implementation process-

DECLARE    a number(2) := 10; BEGIN    a:= 10;   -- check the boolean condition using if statement     IF( a < 20 ) THEN       -- if condition is true then print the following         dbms_output.put_line(‘a is less than 20 ‘ );    END IF;    dbms_output.put_line(‘value of a is : ‘ || a); END; /

When the above code executes at the SQL prompt, it produces the following results-

a is less than 20 value of a is : 10  PL/SQL procedure successfully completed.

Example-2

We have created a table and several records in the PL/SQL variable type, referring to the following statements to manipulate the tables and data-

DECLARE    c_id customers.id%type := 1;    c_sal  customers.salary%type; BEGIN    SELECT  salary     INTO  c_sal    FROM customers    WHERE id = c_id;    IF (c_sal <= 2000) THEN       UPDATE customers        SET salary =  salary + 1000          WHERE id = c_id;       dbms_output.put_line (‘Salary updated‘);    END IF; END; /

When the above code executes at the SQL prompt, it produces the following results-

Salary updated  PL/SQL procedure successfully completed.

PL/SQL If-then statements