You are not allowed to use IF statements in your where clauses. I can see what you are trying to do though and maybe this will work for you:

Create Procedure...

You'd need a union for each column. ie:

CREATE VIEW [dbo].[NiceChildren] As,

SELECT [ID], Child1 FROM [dbo].[Children]

UNION ALL

SELECT [ID], Child2 FROM [dbo].[Children]

UNION ALL

SELECT [ID], Child3 FROM [dbo].[Children]

UNION ALL

SELECT [ID], Child4 FROM [dbo].[Children]

Hi, out of curiosity, does this return the correct data?

SELECT a.raccount,b.Classification

FROM master_tix_header a

JOIN tblProductType b ON a.revent = B.Event

WHERE a.ryear BETWEEN 1999 AND 2002

GROUP BY a.raccount, b.Classification HAVING COUNT(*) = 1

?