使用链接 table 的组值 (MIN) 的结果更新列值

Question

我有两个表 Table 1（主）和 Table 2，与 T1 连接。

I need to delete double entries in Table 1. TO do that before any delete in T1 I must delete or update the data in T2.

The option chosen is to update T2 data to point with entries not to be deleted in T1.

SQL 问题：

我有以下分组：

SELECT min(t1.id) minid
                ,max(t1.id) maxid
                ,t1.t1_value t1valor
                ,t1.group_id grupo
                ,t1.date_begin
                ,t1.date_end
                ,count(*)
            FROM rs2qtt1 t1
            WHERE t1.t1_value LIKE '%B0%'
            GROUP BY t1.t1_value
                ,t1.group_id
                ,t1.date_begin
                ,t1.date_end
            HAVING count(*) > 1
            ORDER BY count(*) DESC
                ,t1.t1_value
                ,t1.group_id
                ,t1.date_begin

如果可能的话，我想做类似的事情来避免 PL/SQL。

UPDATE rs2qtt2 t2
SET t2.rg_id = minid
WHERE t2.rg_id IN ( 
        SELECT maxid max2
        FROM (
            SELECT min(t1.id) minid
                ,max(t1.id) maxid
                ,t1.t1_value t1valor
                ,t1.group_id grupo
                ,t1.date_begin
                ,t1.date_end
                ,count(*)
            FROM rs2qtt1 t1
            WHERE t1.t1_value LIKE '%B0%'
            GROUP BY t1.t1_value
                ,t1.group_id
                ,t1.date_begin
                ,t1.date_end
            HAVING count(*) > 1
            ORDER BY count(*) DESC
                ,t1.t1_value
                ,t1.group_id
                ,t1.date_begin  
            )
        );

但是显然set语句中的minid是不可见的

Answer 1

我认为这可以使用合并来完成：

MERGE INTO rs2qtt2 t2
USING (SELECT min(t1.id) minid
                ,max(t1.id) maxid
                ,t1.t1_value t1valor
                ,t1.group_id grupo
                ,t1.date_begin
                ,t1.date_end
                ,count(*)
            FROM rs2qtt1 t1
            WHERE t1.t1_value LIKE '%B0%'
            GROUP BY t1.t1_value
                ,t1.group_id
                ,t1.date_begin
                ,t1.date_end
            HAVING count(*) > 1
            ORDER BY count(*) DESC
                ,t1.t1_value
                ,t1.group_id
                ,t1.date_begin) t1
ON (t1.maxid = t2.rg_id)
WHEN MATCHED THEN UPDATE SET t2.rg_id = t1.minid;

Answer 2

您可以使用 rs2qtt2 保存的 rowid 在查询中准备所需的值，然后将其用作 merge 查询的源数据，例如

merge into rs2qtt2 dst using (
    select t2.rowid row_id, t1.minid new_id
    from (
        SELECT min(t1.id) minid, max(t1.id) maxid
        FROM rs2qtt1 t1
        WHERE t1.t1_value LIKE '%B0%'
        GROUP BY t1.t1_value, t1.group_id, t1.date_begin, t1.date_end
        HAVING count(*) > 1
    ) t1 inner join rs2qtt2 t2 on (t2.rg_id = t1.maxid)
) src
on (dst.rowid = src.row_id)
when matched then update set dst.rg_id = src.new_id;

这应该有助于避免 ORA-38104 并且应该通过 rowid

直接访问要合并的行

使用链接 table 的组值 (MIN) 的结果更新列值

Update column values with result from group values (MIN) of linked table

sql

oracle

group-by

oracle11g