Problems with Database Link in query

Question

When I run this code:
SELECT NVL2(wbs1.wbs1_seq, wbs1.wbs1, pcn.pron) AS pron
     , h.fy AS data_fy
FROM pcn_list@THE_LINK pcn
     JOIN project@THE_LINK x
     ON x.pcn_seq = pcn.pcn_seq
     JOIN
       SELECT h.project_seq
            , EXTRACT(year FROM (h.data_dt + 92)) AS fy
       FROM pcn_data@THE_LINK h
            JOIN setup@THE_LINK
            ON (
                 setup.data_dt = h.data_dt
                 OR (
                      EXTRACT(year FROM h.data_dt) > DECODE(setup.site, 'TYAD', 2006, 2007)
                      AND h.data_dt < setup.data_dt
                      AND TO_CHAR(h.data_dt, 'MMDD') = '0930'
                 OR (
                      EXTRACT(year FROM h.data_dt) BETWEEN 2000 AND DECODE(setup.site, 'TYAD', 2006, 2007)
                      AND TO_CHAR(h.data_dt, 'MM') = '09'
                      AND h.data_dt = NEXT_DAY(LAST_DAY(h.data_dt) - 7, 'FRIDAY')
       WHERE h.data_dt BETWEEN '01-SEP-06' AND '31-OCT-08'
     ) h
     ON h.project_seq = x.project_seq
     LEFT JOIN wbs1_list@THE_LINK wbs1
     ON (
            wbs1.fiscal_yr = pcn.fiscal_yr
            AND (
                  wbs1.legacy_pron = pcn.pron
                  OR SUBSTR(wbs1.legacy_pron, 1, 2) || SUBSTR(wbs1.legacy_pron, 4) = pcn.pron
          OR (
               TRIM(wbs1.legacy_pron) IS NULL
               AND wbs1.wbs1 = SUBSTR(pcn.pron, 1, 2)
                               || SUBSTR(TO_CHAR(wbs1.start_dt + 92, 'YY'), 1, 1)
                               || SUBSTR(pcn.pron, 3, 1)
                               || SUBSTR(pcn.mission, 1, 1)
                               || SUBSTR(pcn.pron, 4, 5)
                               || DECODE(
                                          SUBSTR(pcn.pron, 12, 1)
                                        , '0', SUBSTR(pcn.pron, 13, 2) || SUBSTR(pcn.pron, 13, 2)
                                        , SUBSTR(pcn.pron, 11, 4)
     LEFT JOIN xref_pron_command cmd1
     ON cmd1.command_cd = SUBSTR(pcn.pron, 11, 2)
     LEFT JOIN xref_pron_command cmd2
     ON cmd2.command_cd = SUBSTR(pcn.pron, 1, 2)
     LEFT JOIN mdms@THE_LINK mdms
     ON mdms.pron = SUBSTR(pcn.pron, 1, 8) || SUBSTR(pcn.pron, 11, 1)
     LEFT JOIN if_fedlog fedlog
     ON fedlog.fsc || fedlog.niin = SUBSTR(pcn.nsn, 1, 13)
     LEFT JOIN awpsammo@THE_LINK ammo
     ON ammo.pron = pcn.pron
     LEFT JOIN if_core_workload c
     ON (
          c.site = 'SITE'
          AND NVL2(wbs1.wbs1_seq, wbs1.wbs1, pcn.pron) = c.pron
          AND h.fy = c.data_fy
WHERE pcn.mission != 'NOP'
AND   x.pmc_cancel_fg = 'F'
AND   NVL(wbs1.cancel_fg, 'F') = 'F'
AND   NVL2(wbs1.wbs1_seq, wbs1.wpc, pcn.wpc) <> 'ZZ'I get:
ORA-00904: "SETUP"."SITE": invalid identifier
ORA-02063: preceding line from THE_LINK
However, if I remove any of the cmd1, cmd2, fedlog, mdms, or ammo joins, it runs properly.
It also runs properly if I remove both "WHERE h.data_dt BETWEEN '01-SEP-06' AND '31-OCT-08'" (line 25) and "AND x.pmc_cancel_fg = 'F'" (third line from the end).
Also, there are three different external sites; the problems happen on two of them, but on a third, the code works as is.
The query also works if:
* I remove the links and run it directly on the external sites
* I add something that makes it return no rows immediately (for example, "AND 0 = 1" as the last line)
* "WHERE h.data_dt BETWEEN '01-SEP-06' AND '31-OCT-08'" is replaced by "WHERE h.data_dt = '30-SEP-09'" (which returns rows)
* For that matter, at one of the problem sites, changing the first date in that WHERE clause to anything between '19-JUN-09' and '29-SEP-09' works, but '18-JUN-09' and earlier causes the error; at the other, the earliest working date is '02-NOV-08'.
All three external databases, as well as the database on which this is run, are running 11.2.0.1.0 64-bit Production.
Any ideas as to what is happening?

Answer 1

sb92075 wrote:
WHERE h.data_dt BETWEEN '01-SEP-06' AND '31-OCT-08'With Oracle characters between single quote marks are STRINGS!
'This is a string, 2009-12-31, not a date'
When a DATE datatype is desired, then use TO_DATE() function.Actually, usually I do (since there's no guarantee as to what the "default" date format will be - besides, the default tends to be 2-year dates). The one line where I don't is really just something I added to speed up the query when testing for the error.
However changing that line to:
WHERE h.data_dt BETWEEN TO_DATE('09/01/2006', 'MM/DD/YYYY') AND TO_DATE('10/31/2008', 'MM/DD/YYYY')causes the same results.