Oracle-Conveting SQL to ANSI SQL - sql

Question

This is regarding converting query to ANSI SQL. I tried writing this query with Oracle old syntax and it threw the following error so I ended up changing it as shown below . After researching, I found that ANSI SQL supports such requirements.
ERROR :a table may be outer joined to at most one other table tips
Here is the query that I wrote which is working but it would be great to know if there are ways this can be re-written in ANSI-SQL or by using old outer join syntax. I am looking for the union queries to be re-written as others in the with clause work fine.
WITH BOM_PARENT AS (
SELECT MX.SAP_MATNR MATNR
, TRIM(I.IPRODUCTION) IPRODUCTION
, TRIM(I.IDRAWING) IDRAWING
, TRIM(M.BCHLD) BCHLD
, M.BSEQ BSEQ
, PX.WERKS WERKS
, M.BPSCP MENGE
, UX.SAP_UOM MEINS
, I.IUMS
FROM XX_MAIN.XX_BPCS_IIM I
, XX_MAIN.XX_BPCS_MPB M
, XX_MAIN.XX_MATER_XREF MX
, XX_MAIN.XX_TRUNK_XREF PX
, XX_MAIN.XX_MP_UNIT_XREF UX
WHERE TRIM(I.IPRODUCTION) = TRIM(M.BPROD)
AND TRIM(MX.PROD_MATNR) = TRIM(I.IPRODUCTION)
AND MX.CONV_FACTOR = TO_CHAR(I.IUMCN)
AND I.IUMS = UX.LEGACY_UOM
AND UX.SOURCE = 'AP'
AND I.SOURCE = PX.SOURCE
AND I.ENTITY = PX.LEGACY_PLANT
AND I.ENTITY = 'SG'
AND I.IITYP = '4'
--AND PX.WERKS IN ('1379')
AND MX.SAP_MTART <> 'ZPRD'
)
, BOM_CHILDS AS
(
SELECT B.*,
X.SAP_MATNR IDNRK
, ROW_NUMBER () OVER ( PARTITION BY B.MATNR,B.WERKS ORDER BY B.MATNR,B.WERKS) ID_ITEM_NO
, X.PROD_MATNR IDNRK_IPRODUCTION
, X.DRAWING_MATNR IDNRK_IDRAWING
FROM BOM_PARENT B
, XX_MAIN.XX_MATER_XREF X
WHERE B.BCHLD = TRIM(X.PROD_MATNR )
AND X.SAP_MTART <> 'ZPRD'
AND X.SOURCE = 'AP'
)
SELECT DISTINCT C.MATNR
, C.IPRODUCTION
, C.IDRAWING
, C.WERKS
, (C.ID_ITEM_NO*10) ID_ITEM_NO
, C.BSEQ
, C.IDNRK
, C.IDNRK_IPRODUCTION
, C.IDNRK_IDRAWING
, C.MENGE BPSCP
, STPO.MENGE STPO_MENGE
, C.MEINS MEINS
, C.IUMS IUMS
, STPO.MEINS STPO_MEINS
FROM BOM_CHILDS C
, XX_MAIN.XX_MAST MAST
, XX_MAIN.XX_STPO STPO
WHERE C.MATNR = MAST.MATNR
AND MAST.STLNR = STPO.STLNR
AND MAST.STLAN = '1'
AND MAST.WERKS = C.WERKS
AND STPO.IDNRK = C.IDNRK
UNION
SELECT DISTINCT C.MATNR
, C.IPRODUCTION
, C.IDRAWING
, C.WERKS
, (C.ID_ITEM_NO*10) ID_ITEM_NO
, C.BSEQ
, C.IDNRK
, C.IDNRK_IPRODUCTION
, C.IDNRK_IDRAWING
, C.MENGE BPSCP
, STPO.MENGE STPO_MENGE
, C.MEINS MEINS
, C.IUMS IUMS
, STPO.MEINS STPO_MEINS
FROM BOM_CHILDS C
, XX_MAIN.XX_MAST MAST
, XX_MAIN.XX_STPO STPO
WHERE C.MATNR = MAST.MATNR(+)
AND MAST.STLNR = STPO.STLNR(+)
AND MAST.STLAN(+) = '1'
AND MAST.WERKS(+) = C.WERKS
AND STPO.IDNRK IS NULL
ORDER BY MATNR,WERKS,ID_ITEM_NO,BSEQ;

Answer 1

This section is probably causing the problem:
FROM BOM_CHILDS C
, XX_MAIN.XX_MAST MAST
, XX_MAIN.XX_STPO STPO
WHERE C.MATNR = MAST.MATNR(+)
AND MAST.STLNR = STPO.STLNR(+)
AND MAST.STLAN(+) = '1'
AND MAST.WERKS(+) = C.WERKS
AND STPO.IDNRK IS NULL
To make this a bit easier, lets rearrange the WHERE clause to order the tables by how they relate:
FROM BOM_CHILDS C
, XX_MAIN.XX_MAST MAST
, XX_MAIN.XX_STPO STPO
-- Joining C to MAST
WHERE C.MATNR = MAST.MATNR(+)
AND C.WERKS = MAST.WERKS(+)
AND MAST.STLAN(+) = '1'
-- Joining MAST to STPO
AND MAST.STLNR = STPO.STLNR(+)
AND STPO.IDNRK IS NULL
We have C joined to MAST using C as the "driver" table and picking up data from MAST where it matches (a left join):
FROM BOM_CHILDS C
LEFT JOIN XX_MAIN.XX_MAST MAST
ON C.MANTR = MAST.MANTR
AND C.WERKS = MAST.WERKS
AND MAST.STLAN = '1'
Then we need to add STPO to the joins:
LEFT JOIN XX_MAIN.XX_STPO STPO
ON MAST.STLNR = STPO.STLNR
AND STPO.IDNRK IS NULL
Putting it all together we get:
FROM BOM_CHILDS C
LEFT JOIN XX_MAIN.XX_MAST MAST
ON C.MANTR = MAST.MANTR
AND C.WERKS = MAST.WERKS
AND MAST.STLAN = '1'
LEFT JOIN XX_MAIN.XX_STPO STPO
ON MAST.STLNR = STPO.STLNR
AND STPO.IDNRK IS NULL
That said, even though (+) works for left/right/outer joins, Oracle recommends not using it:
Oracle recommends that you use the FROM clause OUTER JOIN syntax rather than the Oracle join operator. Outer join queries that use the Oracle join operator (+) are subject to the following rules and restrictions, which do not apply to the FROM clause OUTER JOIN syntax: ...