sql server - Statement blocks in SQL SELECT using IF ELSE -

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i'm trying return different data depending on variable in select. this:

select    if @variable = 'yes'       column1, column2    else       column3 table

what proper way use if condition in sql? or there better alternative i'm trying accomplish?

you can use if statement, you'll need set multiple queries. can use case selecting 1 column or another, not select 1 or multiple in question.

declare @var int = 1;  declare @test table (     col1 int,     col2 int,     col3 int )  insert @test values (1,2,3)  if @var = 1 begin     select  col1, col2        @test end else begin     select  col3        @test end

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