if else in select statement sql code example

Example 1: sql case

-- NOTE: this is for SQL-Oracle specifically

/*
NB: Please like Mingles444 post, I derived this from him/her
*/

-- syntax: (Retrieved from grepper:Mingles444)
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;

-- OUTPUT: B

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: 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;