>>>That's the same version I'm running. I wonder if it was different in VFP6, I don't have it to test.
>>
>>It does not work in VFP6 SP5 either. I can't test any earlier than that. Looking at the help for error 1851 (Selects are not UNION compatible), it says "Data types or sizes of fields being projected in each SELECT statement are not identical" (emphasis mine).
>
>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.

As I wrote previously, I think expressions, not identical to fields, are accepted, but fields are not, for the unequal length.

The following caused an error (not union-compatible) for me (ArtCode C(8), ArtName C(30)):

select ArtName from ArticleMain;
  union select ArtCode from ArticleMain

The following (logically equivalent) did not:

select ArtName from ArticleMain;
  union select padr(ArtCode, 8) from ArticleMain

It seems that converting the field to an expression bypassed the comparison for exact field lengths.

The example, of course, is completely useless.

Hilmar.