Unable to Correct Oracle Error ORA-00905 Missing Keyword in SQL - sql

Question

I've been grinding on this small snippet of simple code for a day and can't find the issue causing the error. As the title states, I am getting error ORA-00905 Missing Keyword when trying to execute the following code:
SELECT DISTINCT DM.DESCRIPTION AS "AGENCY",
DM.DEPT_NO AS "DEPT NO",
CASE
WHEN VMP.RESERVE_DT IS NULL THEN
NULL
ELSE
VMP.RESERVE_DT
END AS "RESV_DT",
CASE
WHEN VMP.EST_PICKUP_DT IS NULL THEN
NULL
ELSE
VMP.EST_PICKUP_DT
END AS "EST_PKUP_DT",
CASE
WHEN VMP.EST_RETURN_DT IS NULL THEN
NULL
ELSE
VMP.EST_RETURN_DT
END AS "EST_RETN_DT",
VMP.EMP_NAME AS "EMPL_NAME",
VMP.UNIT_NO AS "UNIT_NUMBER",
VMP.RENTAL_CLASS_DESCRIPTION AS "RENT_CLS",
VMP.MP_TICKET_NO AS "MP_TKT_NO"
FROM DEPT_MAIN DM
INNER JOIN VIEW_MPOOL VMP ON VMP.DEPT_ID = DM.DEPT_ID
WHERE CASE
WHEN VMP.EST_PICKUP_DT IS NULL THEN
NULL
ELSE
TRUNC(VMP.EST_PICKUP_DT) = TRUNC(SYSDATE)
END
GROUP BY DM.DESCRIPTION,
DM.DEPT_NO,
CASE
WHEN VMP.RESERVE_DT IS NULL THEN
NULL
ELSE
VMP.RESERVE_DT
END,
CASE
WHEN VMP.EST_PICKUP_DT IS NULL THEN
NULL
ELSE
VMP.EST_PICKUP_DT
END,
CASE
WHEN VMP.EST_RETURN_DT IS NULL THEN
NULL
ELSE
VMP.EST_RETURN_DT
END,
VMP.EMP_NAME,
VMP.UNIT_NO,
VMP.RENTAL_CLASS_DESCRIPTION,
VMP.MP_TICKET_NO
ORDER BY CASE
WHEN VMP.EST_PICKUP_DT IS NULL THEN
NULL
ELSE
VMP.EST_PICKUP_DT
END ASC
The basis of this code was generated through an adhoc reporting program and was originally fully-qualified. I stripped out the extraneous quotation marks and assigned table aliases to clean it up. Though I hoped these efforts would help me find the issue, I am unable to find the cause. Thank you for your consideration.

Answer 1

Try to replace this :
WHERE
CASE
WHEN VMP.EST_PICKUP_DT IS NULL THEN NULL
ELSE TRUNC(VMP.EST_PICKUP_DT) = TRUNC(SYSDATE)
END
With :
WHERE
CASE
WHEN VMP.EST_PICKUP_DT IS NULL THEN NULL
ELSE TRUNC(VMP.EST_PICKUP_DT)
END
= TRUNC(SYSDATE)
Please note that this whole expression (and others similar in the query) could be simplified as as :
WHERE
TRUNC(VMP.EST_PICKUP_DT) = TRUNC(SYSDATE)
When VMP.EST_PICKUP_DT is NULL, TRUNC will return NULL, which will not be equal to TRUNC(SYSDATE).

Answer 2

Here:
WHERE
CASE
WHEN VMP.EST_PICKUP_DT IS NULL
THEN NULL
ELSE TRUNC(VMP.EST_PICKUP_DT) = TRUNC(SYSDATE)
END
The END is after a comparison and the case is not being compared against a value.
Switch it like:
WHERE
CASE
WHEN VMP.EST_PICKUP_DT IS NULL
THEN NULL
ELSE TRUNC(VMP.EST_PICKUP_DT)
END = TRUNC(SYSDATE)
Which as horse says, can just be simplified as
WHERE TRUNC(VMP.EST_PICKUP_DT) = TRUNC(SYSDATE)
since a NULL value on VMP.EST_PICKUP_DT will never match TRUNC(SYSDATE).

Answer 3

can't find the issue causing the error
Although I suppose that #EzLo and #a_horse_with_no_name maybe already found error in this case, I can propose a general procedure in debugging such queries.
Step 1: Debug your JOIN- and WHERE- predicates
Comment everything in your SELECT-statement, leave only JOINs, substitute fields with * or constant expression.
E.g.
SELECT 1
-- DISTINCT DM.DESCRIPTION AS "AGENCY",
-- DM.DEPT_NO AS "DEPT NO",
-- CASE
-- ....
-- VMP.RENTAL_CLASS_DESCRIPTION AS "RENT_CLS",
-- VMP.MP_TICKET_NO AS "MP_TKT_NO"
FROM DEPT_MAIN DM
INNER JOIN VIEW_MPOOL VMP ON VMP.DEPT_ID = DM.DEPT_ID
WHERE CASE
WHEN VMP.EST_PICKUP_DT IS NULL THEN
NULL
ELSE
TRUNC(VMP.EST_PICKUP_DT) = TRUNC(SYSDATE)
END
-- GROUP BY DM.DESCRIPTION,
-- ....
-- ORDER BY ..
In case of multiple complex predicates - uncomment one predicate at a time.
Step 2: Debug your GROUP BYs and HAVINGs
Uncomment GROUP BY section and edit fields section of your query.
If you have complex groupby's - uncomment by one field at time.
Start from simplest to complex
SELECT
DM.DESCRIPTION
,DM.DEPT_NO
-- ...
FROM DEPT_MAIN DM
INNER JOIN VIEW_MPOOL VMP ON VMP.DEPT_ID = DM.DEPT_ID
WHERE CASE
WHEN VMP.EST_PICKUP_DT IS NULL THEN
NULL
ELSE
TRUNC(VMP.EST_PICKUP_DT) = TRUNC(SYSDATE)
END
GROUP BY DM.DESCRIPTION
,DM.DEPT_NO
Copy-paste your GROUP BYs into SELECT fields section.
Step 3: Debug you aggregates, field transformation and renames
Now you have correct SELECT-query but probably not in the shape you want.
Step 4: Debug ORDER BYs
You have correct shape and in last step you need to ORDER BY your data.
If you have decent editor/IDE you can find source of error in 5-10 minutes even in cases of complex queries (and even RDBMS engine bugs)
P.S.
It's better to note which version of RDBMS you are using.