Yes, it's legal. Sql Server is quite flexible in that matter. The following is legal too

Select SPACE(1) FROM mytable UNION SELECT cName FROM someothertable

The size of the result column would be equal the lenght of cName in either case.

>FWIW, this is legal to do in Oracle. I wonder if it is legal in SQL Server.
>
>>I need to amend my initial reply here. What does not work is a union where the same field in the second query is a smaller size. For example

SELECT cName FROM mytable UNION SELECT cName FROM someothertable

results in error 1851 if cName is C(10) in mytable and C(1) in someothertable (i.e., smaller but not identical).
>>
>>No error is generated if you use space(1) in the second query

SELECT cName FROM mytable UNION SELECT SPACE(1) FROM someothertable

although the result is not necessarily what one would expect.