Control structures syntax; IF THEN ELSE, CASE, WHILE .
IF THEN ELSE
The IF THEN ELSE syntax in TSQL is kinda weird if you ask me … I forget them ‘all the time’, created examples below for my reference.
IF THEN

if 1 = 1


begin


print 'true'


end




go

IF THEN – short notation
IF THEN ELSE

if 1 = 1


begin


print 'true'


end




else




begin


print 'false'


end




go

IF THEN ELSE – short notation

if 1 = 1


print 'true'


else


print 'false'




go

Multiple IF THEN ELSE blocks

if 1 = 1


begin


print '1 = 1'


end


else


if 1 = 2


begin


print '1 = 2'


end


else


if 1 = 3


begin


print '1 = 3'


end




go

CASE
TSQL has the CASE control structure …

declare @i int, @r int




set @i = 1






set @r =


case @i


when 1 then 1


when 2 then 2


else 0


end




print @r






go

WHILE
Eternal loop

while 1 = 1


print 'true'




go

Simple WHILE loop

declare @i int


set @i = 0




while @i < 10


begin


print @i


set @i = @i + 1


end




go

Beautifully concise!
The best page on the internet for TSQL control structures!
Thank you.