多个表上的多个LEFT OUTER JOIN

Question

I would like to convert the following Oracle SQL query syntax (Use LEFT OUTER JOIN instead of (+) ):

SELECT      *
FROM        TABLEA A, TABLEB B, TABLEC C, TABLED D
WHERE       MY_COL = @col_val
AND         A.X = B.X(+)
AND         B.Y = C.Y(+)
AND         D.Z=A.Z

Here is what I tried so far:

SELECT *
FROM TABLEA A, TABLEB B, TABLEC C, TABLED D
LEFT OUTER JOIN TABLEA A ON A.X = B.X
LEFT OUTER JOIN TABLEC C ON B.Y = C.Y
WHERE MY_COL = @col_val
AND D.Z = A.Z;

But I get the error :

"ORA-00904: "B"."X" : invalid identifier"

Answer 1

The join on D is an inner join, the rest are left outer joins:

SELECT *
FROM TABLEA A JOIN
     TABLED D
     ON D.Z = A.Z LEFT JOIN
     TABLEB B
     ON A.X = B.X LEFT JOIN
     TABLEC C
     ON B.Y = C.Y 
WHERE MY_COL = @col_val;

I always start chains of joins with inner joins followed by the left outer join . I never use right join , and full join rather rarely. The inner joins define the rows in the result set, so they come first.

Answer 2

You don't should mix explicit and implicit sintax

  SELECT *
  FROM TABLEA A 
  INNER JOIN TABLEL L ON L.Z = A.Z
  LEFT OUTER JOIN TABLEB B ON A.X = B.X
  LEFT OUTER JOIN TABLEC C ON B.Y = C.Y
  WHERE A.MY_COL = @col_val

you should use inner join (or join) for TABLEL

Answer 3

Try this:

SELECT *
FROM TABLEA A
LEFT OUTER JOIN TABLEB B ON A.X = B.X
LEFT OUTER JOIN TABLEC C ON B.Y = C.Y
INNER JOIN TABLED D ON D.Z = A.Z
WHERE MY_COL = @col_val

TABLEB and TABLEC goes in LEFT OUTER JOIN (you have used +), instead TABLED goes in INNER JOIN