lightdb 支持从父查询中返回子查询表中的 rowid
背景
在如下的 sql 中,
select rowid from (select 1 from t);
lightdb 24.1 以前会直接报错,说找不到 rowid 列。为了兼容 Oracle, 在 24.1 中,我们选择将告知子查询除了返回子查询应有的列之外,还需返回 rowid 列。
样例
以下样例 sql 说明了 lightdb 24.1 中支持的 rowid 的功能:
-- rowid is passed down to table t1
select rowid from (select 1 from t1);
select rowid, a from (select a from t1);
-- rowid is passed down to table t1
select a.rowid from (select 1 from t1) a;
--= error, `a` could not be referenced from `public` schema as `a` is not a regular table
select public.a.rowid from (select 1 from t1) a;
--
-- multi-level subqueries
--
select rowid from (select 1 from (select 1 from t1));
select rowid from (select 1 from (select 1 from (select 1 from (select 1 from (select 1 from (t1))))));
-- lateral join
select t2.rowid from t2 cross join lateral (select t1.a from t1 where t1.rowid = t2.rowid) a;
-- rowid should not pass down to subquery
select t1.rowid from (select t1.a from t1, t2), t1;
posted on 2024-04-11 16:26 winter-loo 阅读(16) 评论(0) 收藏 举报
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