Hi!

Try to take INV in query into '()' and add 'm' - for case if you have such field in current table (VFP takes field value even when memory variable exists).
In addition, put space before each semicolon, otherwise you risk to have even syntax error:

STOR ALLT(THISFORM.INVNUMB1.VALUE) TO INV
SELECT * ;
FROM transactions!factgrostete INNER JOIN transactions!factgros ;
ON Factgrostete.invnumb = Factgros.invnumb ;
WHERE Factgrostete.invnumb = (m.INV) ;
INTO CURSOR QUERY1


>Can someone explain to me why this works:
>
>STOR ALLT(THISFORM.INVNUMB1.VALUE) TO INV
>SELECT *;
> FROM transactions!factgrostete INNER JOIN transactions!factgros ;
> ON Factgrostete.invnumb = Factgros.invnumb;
> WHERE Factgrostete.invnumb = "&INV";
> INTO CURSOR QUERY1
>
>And this does not:
>
>STOR ALLT(THISFORM.INVNUMB1.VALUE) TO INV
>SELECT *;
> FROM transactions!factgrostete INNER JOIN transactions!factgros ;
> ON Factgrostete.invnumb = Factgros.invnumb;
> WHERE Factgrostete.invnumb = INV;
> INTO CURSOR QUERY1
>
>Whit this one I get an Operand mismatch. The INV value is character and the invnumb field is character.