SQL Server Judgment statement (IF Else/case when)

1. IF ELSE

cannot be used in select, only blocks, such as:

IF ...

BEGIN

...

END

else (note that there is no else if, to be implemented can only be judged in the following block)

BEGIN

...

END

Reference: Https://msdn.microsoft.com/en-us/library/ms182587.aspx

2. Case and then ELSE END

Can be used in select, but include end end

Case ...

When ... Then ...

ELSE ... (can be omitted)

END

Reference: Https://msdn.microsoft.com/en-us/library/ms181765.aspx

SQL Server Judgment statement (IF Else/case when)