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Update FAQ.

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Bruce Momjian 2000-06-13 08:07:50 +00:00
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doc/FAQ
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@ -102,6 +102,7 @@
Why? Why?
4.22) How do I create a column that will default to the current time? 4.22) How do I create a column that will default to the current time?
4.23) Why are my subqueries using IN so slow? 4.23) Why are my subqueries using IN so slow?
4.24) How do I do an outer join?
Extending PostgreSQL Extending PostgreSQL
@ -992,6 +993,21 @@ BYTEA bytea variable-length array of bytes
WHERE EXISTS (SELECT col2 FROM TAB2 WHERE col1 = col2) WHERE EXISTS (SELECT col2 FROM TAB2 WHERE col1 = col2)
We hope to fix this limitation in a future release. We hope to fix this limitation in a future release.
4.24) How do I do an outer join?
PostgreSQL does not support outer joins in the current release. They
can be simulated using UNION and NOT IN. For example, when joining
tab1 and tab2, the following query does an outer join of the two
tables:
SELECT tab1.col1, tab2.col2
FROM tab1, tab2
WHERE tab1.col1 = tab2.col1
UNION ALL
SELECT tab1.col1, NULL
FROM tab1
WHERE tab1.col1 NOT IN (SELECT tab2.col1 FROM tab2)
ORDER BY tab1.col1
_________________________________________________________________ _________________________________________________________________
Extending PostgreSQL Extending PostgreSQL