Question

How to dynamically add conditions to the TSQL Where clause?

I’m trying to avoid selecting between two complete Select statements. The following is very similar, but less complicated, than my actual code.

SELECT COUNT(*)
FROM   MyTable
WHERE  ShipDate >= @FirstDayOfMonth
AND    ShipDate <  @LastDayOfMonth
AND    OrderType = 1
AND    NOT OrderCode LIKE '%3'
AND    NOT OrderCode LIKE '%4';

I would like to be able to add or remove the last two conditions depending on the value of a stored procedure parameter.

i.e.: if @ExcludePhoneOrders = False , don’t use the last two Where clause conditions.

Answer 1

I’m not sure if you meant to include or exclude, but here is a stab at it.

SELECT COUNT(*)
FROM   MyTable
WHERE  ShipDate >= @FirstDayOfMonth
AND    ShipDate <  @LastDayOfMonth
AND    OrderType = 1
AND    (@ExcludePhoneOrders = False OR (NOT OrderCode LIKE '%3' AND NOT OrderCode LIKE '%4'));