SQL IF ELSE code example

Example 1: else if sql server

IF (Expression 1)
BEGIN
   Statement 1;
END

ELSE IF (Expression 2)
BEGIN
   Statement 2;
END
..........
ELSE 
BEGIN
   Default Statement;
END

Example 2: sql if else

-- PL/SQL
BEGIN
    IF my_val = 1 THEN [...]
    ELSE [...]
    END IF;
END;
-- In a query (DUAL is for Oracle)
SELECT CASE WHEN my_col = 1 THEN 'Ok' ELSE 'Ko' END AS my_result
FROM DUAL;

Example 3: if else sql

IF Boolean_expression
BEGIN
    -- Statement block executes when the Boolean expression is TRUE
END
ELSE
BEGIN
    -- Statement block executes when the Boolean expression is FALSE
END

Example 4: case statement in sql

Case Statement basically
Like IF - THEN - ELSE statement.

The CASE statement goes through conditions
and returns a value when the
first condition is met and
once a condition is true,
it will stop reading and return the result.
If no conditions are true,
it returns the value in the ELSE clause.

If there is no ELSE part and
no conditions are true, it returns NULL.

FOR EXAMPLE =

CASE
    WHEN condition1 THEN result1
    WHEN condition2 THEN result2
    WHEN conditionN THEN resultN
    ELSE result
END 

-- example:
SELECT 
	CASE
      WHEN (1+6 = 6) THEN 'A'
      WHEN (1+6 = 7) THEN 'B'
      WHEN (1+6 = 8) THEN 'C'
      ELSE 'D'
	END 
FROM DUAL;

Result would be 'B' since it is the first
correct answer

Example 5: t-sql if else

IF 1=1
	SELECT 1
ELSE
	SELECT 0
-- returns 1

-- Definition
IF Boolean_expression   
     { sql_statement | statement_block }   
[ ELSE   
     { sql_statement | statement_block } ]

Example 6: SQL IF ELSE

SELECT CASE             
            WHEN A + B > C AND B + C > A AND A + C > B THEN
                CASE 
                    WHEN A = B AND B = C THEN 'Equilateral'
                    WHEN A = B OR B = C OR A = C THEN 'Isosceles'
                    ELSE 'Scalene'
                END
            ELSE 'Not A Triangle'
        END
FROM TRIANGLES;