IF {ELSE IF} Construct

Hi

Since there is no IF {ELSE IF} constructs in TSQL, I assume the following will do the equivalent of ELSE IF, please verify. Thanx :)

IF condition
BEGIN
-- some TSQL
END
ELSE IF condition
BEGIN
-- some TSQL
END
ELSE
BEGIN
-- some TSQL
END

JamesPlease comment on any deviation from standard programming that this IF ELSE IF construct may introduce. I am too novice to see it.

Cheers

James|||This should work, but your code will be more readable if you can use a CASE statement instead.

blindman|||true
but isn't IF and ELSE more efficient than CASE
I assume that because what i said is true in general programming

cheers
james|||For a single criteria IF ELSE is probably more efficient, but when you start nesting IF statements I doubt there is any difference. The db engine has to make the same logical comparisons in either case.

Evaluation of a CASE statement completes as soon as a match is found, and further criteria are not considered. I'm not sure if this is true of nested IF/ELSE statements; ie, the optimizer may evaluate the entire statement. Perhaps someone else on the forum knows how the optimizer handles this scenario.

Truth is, neither of these is a very fast operation when performed against large tables. You gotta do what you gotta do.

blindman|||Originally posted by nano_electronix
Hi

Since there is no IF {ELSE IF} constructs in TSQL, I assume the following will do the equivalent of ELSE IF, please verify. Thanx :)

IF condition
BEGIN
-- some TSQL
END
ELSE IF condition
BEGIN
-- some TSQL
END
ELSE
BEGIN
-- some TSQL
END

James

I think this is the correct solution. Lets say "condition" refers to weekend day, a holiday or a week day flag and "TSQL" refers to three totaly diffrent queries. Your code would be resonable.

Now lets say "TSQL" is identical except for the treatment of a date column and all you want is the words "Holiday", "Weekend" or "Weekday" returned in your query, a CASE statment might be the better choice.

Clear as mud?|||agree :)