15.10 - Example: Left Outer Join Usage - Teradata Database

Teradata Database SQL Data Definition Language Syntax and Examples

prodname
Teradata Database
vrm_release
15.10
created_date
December 2015
category
Programming Reference
featnum
B035-1144-151K

The first recursive view definition demonstrates a correct use of a left outer join, which is highlighted in bold. The usage is valid because the recursive relation in the recursive statement of the view definition is used as the outer relation in the left outer join.

    CREATE RECURSIVE VIEW rec (f1, mycount) AS (
      SELECT a1, 0 AS mycount
      FROM nonrec
    UNION ALL
      SELECT a2, mycount + 1
      FROM rec LEFT OUTER JOIN nonrec ON nonrec.a1 = rec.f1
      WHERE rec.mycount <= 100);

The second recursive view definition demonstrates a non-valid use of a left outer join, which is highlighted in bold. The usage is not valid because the recursive relation in the recursive statement of the view definition is used as the inner relation in the left outer join.

    CREATE RECURSIVE VIEW rec (f1, mycount) AS (
      SELECT a1, 0 AS mycount
      FROM nonrec
    UNION ALL
      SELECT a2, mycount + 1
      FROM nonrec LEFT OUTER JOIN rec ON nonrec.a1 = rec.f1
      WHERE rec.mycount <= 100);

You can use left outer joins without restriction in the seed statement of a recursive view definition.