Sql 根据informix中复杂select语句的输出删除外键约束？

我正在使用INFORMIX数据库

我在表中添加了forign键，但没有给它命名，例如

ALTER TABLE myreport ADD CONSTRAINT FOREIGN KEY (rid) REFERENCES report(id), ADD CONSTRAINT FOREIGN KEY (uid) REFERENCES user(id);

我希望根据select语句的输出删除其forign键约束，如下所示：

ALTER TABLE myreport DROP CONSTRAINT (
   SELECT b.constrname
       FROM
           systables a, sysconstraints b, sysindexes c, syscolumns d
       WHERE
           a.tabname = 'myreport' AND (d.colname='rid' or d.colname='uid')
       AND
           b.tabid = a.tabid
       AND
           c.idxname = b.idxname
       AND
           d.tabid = a.tabid
       AND
       (
           d.colno = c.part1 or d.colno = c.part2 or d.colno = c.part3 or d.colno = c.part4 or
           d.colno = c.part5 or d.colno = c.part6 or d.colno = c.part7 or d.colno = c.part8 or
           d.colno = c.part9 or d.colno = c.part10 or d.colno = c.part11 or d.colno = c.part12 or
           d.colno = c.part13 or d.colno = c.part14 or d.colno = c.part15 or d.colno = c.part16
       )
);

引发错误

201:发生语法错误。

但当我单独运行它时，它工作正常，并给出如下输出：

ALTER TABLE myreport DROP CONSTRAINT (
   SELECT b.constrname
       FROM
           systables a, sysconstraints b, sysindexes c, syscolumns d
       WHERE
           a.tabname = 'myreport' AND (d.colname='rid' or d.colname='uid')
       AND
           b.tabid = a.tabid
       AND
           c.idxname = b.idxname
       AND
           d.tabid = a.tabid
       AND
       (
           d.colno = c.part1 or d.colno = c.part2 or d.colno = c.part3 or d.colno = c.part4 or
           d.colno = c.part5 or d.colno = c.part6 or d.colno = c.part7 or d.colno = c.part8 or
           d.colno = c.part9 or d.colno = c.part10 or d.colno = c.part11 or d.colno = c.part12 or
           d.colno = c.part13 or d.colno = c.part14 or d.colno = c.part15 or d.colno = c.part16
       )
);

选择：

SELECT b.constrname
       FROM
           systables a, sysconstraints b, sysindexes c, syscolumns d
       WHERE
           a.tabname = 'myreport' AND (d.colname='rid' or d.colname='uid')
       AND
           b.tabid = a.tabid
       AND
           c.idxname = b.idxname
       AND
           d.tabid = a.tabid
       AND
       (
           d.colno = c.part1 or d.colno = c.part2 or d.colno = c.part3 or d.colno = c.part4 or
           d.colno = c.part5 or d.colno = c.part6 or d.colno = c.part7 or d.colno = c.part8 or
           d.colno = c.part9 or d.colno = c.part10 or d.colno = c.part11 or d.colno = c.part12 or
           d.colno = c.part13 or d.colno = c.part14 or d.colno = c.part15 or d.colno = c.part16
       )

ALTER TABLE cuicscheduledreports DROP CONSTRAINT (r169_278, r169_279)

给出：

constrname  r169_278
constrname  r169_279
constrname  r169_280

更改表格：

SELECT b.constrname
       FROM
           systables a, sysconstraints b, sysindexes c, syscolumns d
       WHERE
           a.tabname = 'myreport' AND (d.colname='rid' or d.colname='uid')
       AND
           b.tabid = a.tabid
       AND
           c.idxname = b.idxname
       AND
           d.tabid = a.tabid
       AND
       (
           d.colno = c.part1 or d.colno = c.part2 or d.colno = c.part3 or d.colno = c.part4 or
           d.colno = c.part5 or d.colno = c.part6 or d.colno = c.part7 or d.colno = c.part8 or
           d.colno = c.part9 or d.colno = c.part10 or d.colno = c.part11 or d.colno = c.part12 or
           d.colno = c.part13 or d.colno = c.part14 or d.colno = c.part15 or d.colno = c.part16
       )

ALTER TABLE cuicscheduledreports DROP CONSTRAINT (r169_278, r169_279)

显示成功日志

因此，我需要一组查询，这些查询将以动态方式实现我的需求，因为它将用作不同系统上的数据库迁移

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DROP CONSTRAINT不允许对约束名称进行子查询。约束名称必须显式命名

此处记录了DROP CONSTRAINT的语法：

只允许使用逗号分隔的名称列表，不允许使用子查询

正如您所发现的，您必须分两步完成此任务

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在将来，您应该避免虚构语法并期望它能够工作。查看手册了解语法选项。

那么有什么问题吗？那么您能给我一组查询，这些查询可以在任何步骤中完成，因为此查询是在不同系统上对db的迁移对不起，我不知道您使用的是什么迁移工具或过程。没有迁移工具，我们编写了一些sql文件集，我们使用一些脚本一个接一个地在db上执行，所以我需要一组查询语句，它将在不同的系统上执行，它应该删除ConstraintsOkay，那么您已经有了解决方案。你把它贴在上面的问题上了。执行SELECT以获取约束的名称，然后使用该结果形成ALTERTABLE语句。