How do I convert a “legacy” left outer join statement in Oracle?

问题

I have two tables (A and G) in an Oracle database that can be joined together based off an account number. The one caveat to this is that one of the tables (G) has about 80 fewer records than the other. When I query the two tables together, I need to get all of the rows, so that we see NULL data in the columns for the missing 80 rows.

I currently have an Oracle statement that performs a left outer join query using the following "legacy" syntax:

SELECT A.AccountNo,
       A.ParcelNo,
       A.LocalNo,
       A.PrimaryUseCode, 
       A.DefaultTaxDistrict,
       RTRIM(G.Section),
       RTRIM(G.Township),
       RTRIM(g.Range)

  FROM tblAcct A, tblAcctLegalLocation G

 WHERE A.verstart <= '20100917999' AND A.verend > '20100917999' AND A.DefaultTaxDistrict = '2291' 
       AND (SUBSTR(A.AccountNo,1,1) = 'R' or SUBSTR(A.AccountNo,1,1)= 'I') 
       AND SUBSTR(a.ParcelNo,1,1)<> '7' and substr(a.ParcelNo,1,1)<>'8'
       AND A.AcctStatusCode IN ('A', 'T', 'E') 
       AND A.AccountNo = G.AccountNo(+)
       AND G.verstart(+) <= '20100917999' and G.verend(+) > '20100917999'
ORDER BY A.ParcelNo, A.LocalNo

I'm trying to convert this query into a "standard" LEFT JOIN type query since I'm told the newer versions of Oracle support this syntax. I've tried the basic

LEFT OUTER JOIN ON A.AccountNo = G.AccountNo

but this doesn't seem to work. My queries wind up returning 80 rows fewer than the full amount.

Can anybody tell me what I'm missing or how to format the query properly?

回答1:

Use:

  SELECT a.AccountNo,
         a.ParcelNo,
         a.LocalNo,
         a.PrimaryUseCode, 
         a.DefaultTaxDistrict,
         TRIM(g.Section),
         TRIM(g.Township),
         TRIM(g.Range)
     FROM tblAcct A
LEFT JOIN tblAcctLegalLocation g ON g.accountno = a.accountno
                                AND g.verstart <= '20100917999' 
                                AND g.verend > '20100917999'
    WHERE a.verstart <= '20100917999' 
      AND a.verend > '20100917999' 
      AND a.DefaultTaxDistrict = '2291' 
      AND SUBSTR(a.AccountNo,1,1) IN ('R', 'I') 
      AND SUBSTR(a.ParcelNo,1,1) NOT IN ('7', '8')
      AND a.AcctStatusCode IN ('A', 'T', 'E') 
 ORDER BY a.ParcelNo, a.LocalNo

Everything you see marked with the (+) must be included in the OUTER join criteria. In an outer JOIN, the criteria is applied before the join.

来源：https://stackoverflow.com/questions/4001045/how-do-i-convert-a-legacy-left-outer-join-statement-in-oracle

标签

sql

Oracle

outer-join