SQL: IF clause within WHERE clause

Question

Is it possible to use an IF clause within a WHERE clause in MS SQL?

Example:

WHERE

    IF IsNumeric(@OrderNumber) = 1

        OrderNumber = @OrderNumber

    ELSE

        OrderNumber LIKE '%' + @OrderNumber + '%'

Answer 1

You can try using the CASE statement like this: 

Refer to this video to learn Case Statements in detail:

WHERE OrderNumber LIKE

  CASE WHEN IsNumeric(@OrderNumber) = 1 THEN 

    @OrderNumber 

  ELSE

    '%' + @OrderNumber

  END