Subquery in the From Clause

Question

I have a query the contains a subquery in the from clause. The problem is how to join one of the tables in the subquery to one of the main tables. If I hard a value, the query runs, but using a table.column produced an "invalid column name" error.
Examples of both are below.
This one works
SELECT a.pay_rate, a.bill_rate, a.frequency, c.value
FROM SYSADM.ps_pb_wkord_sq_rte a, SYSADM.ps_md_erncd_action b,
SELECT DISTINCT z.value
FROM SYSADM.ps_md_erncd_action z
WHERE z.md_action = 'CALC_BURD' AND
z.system_id = 'PB' AND
z.erncd = 'REG' AND **This is the line in question**
z.effdt = (
SELECT MAX(z_ed.effdt)
FROM SYSADM.ps_md_erncd_action z_ed
WHERE z.setid = z_ed.setid AND
z.erncd = z_ed.erncd AND
z.effdt = z_ed.effdt AND
z.system_id = z_ed.system_id AND
z.md_action = z_ed.md_action AND
z_ed.effdt <= TO_DATE('04/01/2001','MM/DD/YYYY'))) c
WHERE a.erncd = b.erncd AND
b.effdt = (
SELECT MAX(b_ed.effdt)
FROM SYSADM.ps_md_erncd_action b_ed
WHERE b.setid = b_ed.setid AND
b.erncd = b_ed.erncd AND
b.effdt = b_ed.effdt AND
b.system_id = b_ed.system_id AND
b.md_action = b_ed.md_action AND
b_ed.effdt <= TO_DATE('04/01/2001','MM/DD/YYYY')) AND
a.group_id = 'PSD01' AND
a.workorder_no = 'H00034758' AND
a.assignment_no = 'H00034758-001' AND
b.system_id = 'PB' AND
b.md_action = 'EARN_TYPE' AND
b.value = 'R';
This one produces the error
SELECT a.pay_rate, a.bill_rate, a.frequency, c.value
FROM SYSADM.ps_pb_wkord_sq_rte a, SYSADM.ps_md_erncd_action b,
SELECT DISTINCT z.value
FROM SYSADM.ps_md_erncd_action z
WHERE z.md_action = 'CALC_BURD' AND
z.system_id = 'PB' AND
z.erncd = a.erncd AND **This is line in question**
z.effdt = (
SELECT MAX(z_ed.effdt)
FROM SYSADM.ps_md_erncd_action z_ed
WHERE z.setid = z_ed.setid AND
z.erncd = z_ed.erncd AND
z.effdt = z_ed.effdt AND
z.system_id = z_ed.system_id AND
z.md_action = z_ed.md_action AND
z_ed.effdt <= TO_DATE('04/01/2001','MM/DD/YYYY'))) c
WHERE a.erncd = b.erncd AND
b.effdt = (
SELECT MAX(b_ed.effdt)
FROM SYSADM.ps_md_erncd_action b_ed
WHERE b.setid = b_ed.setid AND
b.erncd = b_ed.erncd AND
b.effdt = b_ed.effdt AND
b.system_id = b_ed.system_id AND
b.md_action = b_ed.md_action AND
b_ed.effdt <= TO_DATE('04/01/2001','MM/DD/YYYY')) AND
a.group_id = 'PSD01' AND
a.workorder_no = 'H00034758' AND
a.assignment_no = 'H00034758-001' AND
b.system_id = 'PB' AND
b.md_action = 'EARN_TYPE' AND
b.value = 'R';
Any help is greatly appreciated.
Thanks,
JD Lippard

Answer 1

Hi JD,
your code is very difficult to read to i will give you some general information.
SELECT t1.c1,t1.c2
FROM table t1
, (SELECT t2.col1 alias1
, t2.col2 alias2
, a.s.o.
FROM anytable t2
) tablealias
WHERE t1.c1 = tablealias.alias1
You can select any columns inside this 'dynamic view' whichever you need for a join. Independent if you print them or not.
But you cannot join INSIDE this dynamic view to outer tables like
SELECT t1.c1,t1.c2
FROM table t1
, (SELECT t2.col1 alias1
, t2.col2 alias2
, a.s.o.
FROM anytable t2
WHERE t1.c2 = t2.col2
) tablealias
WHERE bla
Maybe it helps a bit.
Cheers,
Udo