--- In firebird-support@yahoogroups.com, JoshCooper@u... wrote:

>
> Do firebird (1.5stable) support subqueries? I have the following

statement:

>
> SELECT a.ASSY_CODE FROM MATRIX m
> INNER JOIN MATRIX_CELL_ASSY mca
> ON m.MATRIX_ID = mca.MATRIX_ID WHERE MATRIX_LIB_ID = 3 And MATRIX_ID

= 87

> INNER JOIN ASSEMBLY a
> ON mca.ASSY_ID = a.ASSY_ID WHERE a.ASSY_LIB_ID = mca.ASSY_LIB_ID
>
> which appears to be correct, eachy INNER JOIN works on its on, but I

get an

> error when i get to the second inner join.
> Is it a syntax issue (grouping of some sort) or can this just not be

done

> currently?

Josh, pay more attention to TFM ;) WHERE should be written after ALL
JOIN conditions, not many times after each to which it is related, so:

SELECT a.ASSY_CODE
FROM MATRIX m
INNER JOIN MATRIX_CELL_ASSY mca
ON m.MATRIX_ID = mca.MATRIX_ID
INNER JOIN ASSEMBLY a
ON mca.ASSY_ID = a.ASSY_ID WHERE a.ASSY_LIB_ID = mca.ASSY_LIB_ID
WHERE MATRIX_LIB_ID = 3 And MATRIX_ID = 87

Though you can avoid usage of WHERE at all and apply it's condition
directly in JOIN, like

SELECT a.ASSY_CODE
FROM MATRIX m
INNER JOIN MATRIX_CELL_ASSY mca
ON m.MATRIX_ID = mca.MATRIX_ID
And MATRIX_LIB_ID = 3 And MATRIX_ID = 87
INNER JOIN ASSEMBLY a
ON mca.ASSY_ID = a.ASSY_ID WHERE a.ASSY_LIB_ID = mca.ASSY_LIB_ID

Can't surely say what is better, both will work.

Best regards,
Alexander.