Operations that Require Temporary Segments (26)

The following statements sometimes require the use of a temporary segment:
■ CREATE INDEX
■ SELECT ... ORDER BY
■ SELECT DISTINCT ...
■ SELECT ... GROUP BY
■ SELECT . . . UNION
■ SELECT ... INTERSECT
■ SELECT ... MINUS
Some unindexed joins and correlated subqueries can require use of a temporary
segment. For example, if a query contains a DISTINCT clause, a GROUP BY, and an
ORDER BY, Oracle can require as many as two temporary segments.

1. 以上7種情況可能用到臨時段
2. Oracle一條SQL最多可以申請兩個臨時段.

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