>When I use macro substitution in queries on larger tables it is considerably slower than ruuning the query with the values instead.
>Does anybody have any ideas on this ?
>Thanks for any help in advance.

Straight from the help file:
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Tip Whenever possible, use a name expression instead of macro substitution. A name expression operates like macro substitution. However, a name expression is limited to passing character strings as names. Use a name expression for significantly faster processing if a command or function accepts a name (a file name, window name, menu name, and so on).

For additional information on name expressions, see Overview of the Language.

While the following commands are acceptable:

STORE 'customer' TO gcTableName
STORE 'company' TO gcTagName
USE &gcTableName ORDER &gcTagName

use a name expression instead:

USE (gcTableName) ORDER (gcTagName)
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Post your code and maybe someone will point out an alternative to macro substitution.

Jon