T-SQL IIF() Function

The T-SQL (Transact-SQL) IIF() function returns a value if a condition is TRUE, or another value if a condition is FALSE.

IIF(condition, value_if_true, value_if_false)

`condition`	`Required.` Specify the value to test.
`value_if_true`	`Required.` Specify the value to return if condition is TRUE.
`value_if_false`	`Required.` Specify the value to return if condition is FALSE.

Returns value based on the condition.

The example below shows the usage of IIF() function.

SELECT IIF(100>200, 'TRUE', 'FALSE');
Result: 'FALSE'

SELECT IIF(100<200, 'T', 'F');
Result: 'T'

SELECT IIF(100<200, 500, 600);
Result: 500

Consider a database table called Sample with the following records:

The below query is used to compare records of column x and y. Based on the comparison, the result is recorded.

SELECT *, IIF(x > y, 'TRUE', 'FALSE') AS IIF_Value FROM Sample;

This will produce the result as shown below:

Data	x	y	IIF_Value
Data 1	10	8	TRUE
Data 2	20	22	FALSE
Data 3	30	31	FALSE
Data 4	40	39	TRUE
Data 5	50	53	FALSE