I tried this

select * from IndustryMap

WHERE 1 =1

AND id_cusip = COALESCE(@cusip,id_cusip)

AND ticker = COALESCE(@ticker,ticker)

AND exch_code = COALESCE(@exchangeCode,exch_code)

and was ready to scream Hurray but realized that

when any of the columns have a null value

this won't work. Because "AND col = NULL" is not valid.

Keep searching.... 🙂