sql - 如何在 AS400 中执行 DB2-SQL 删除前 N …

Question

SELECT * FROM DB FETCH 100 ROW ONLY -> 没问题。

仅从 DB FETCH 100 ROW 中删除 -> 为什么不呢？

Answer 1

仅获取前 xxx 行

当您不需要完整的结果集时，基本上只是一种性能捷径。手册说:

Specification of the fetch-first-clause in a select-statement makes the result table read-only. A read-only result table must not be referred to in an UPDATE or DELETE statement. The fetch-first-clause cannot appear in a statement containing an UPDATE clause.

这应该可行

DELETE FROM mytbl
WHERE pk IN (SELECT pk FROM mytbl
             FETCH FIRST 100 ROWS ONLY
            )