多表关联同时更新多条不同的记录方法分享
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多表关联同时更新多条不同的记录方法分享，
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以下为测试例子。
1.首先创建两张临时表并录入测试数据：
<div class="codetitle"><a style="CURSOR: pointer" data="44677" class="copybut" id="copybut44677" onclick="doCopy('code44677')"> 代码如下:
<div class="codebody" id="code44677">
create table #temptest1
(
id int,
name1 varchar(50),
age int
)
create table #temptest2
(
id int,
age int
)
查询出此时的表数据为：
#temptest1 #temptest2
只用一句sql，不能用循环。
实现方法如下：
sql Server 2008 Merge命令写法：
using(select age,id from #temptest2) t2
on t1.id = t2.id
when matched then
update set t1.age = t2.age
sql。
如何一次性更新多条不同值的记录
标题可能没说清楚，假设有这样两张表：
create table testA(
id number,
eng varchar2(3),
chi varchar2(3)
)
create table testB(
id number,
chi varchar2(3)，
anythingother varchar2(1)
)
现有记录
testA：
ID ENG CHI
===============
1 a 一
2 b 二
3 c 三
testB:
ID ENG CHI ANY....
=================
1 d 四
2 e 五
3 f 六
我想把testB中的记录的ENG,CHI字段更新到testA中去，以ID来对应。 CODE:
sql> set autot on
sql> update ta set ta.b=(select tb.b from tb where ta.a=tb.a) where exists (select 1 from tb where ta.a=tb.a);
已更新4行。
已用时间: 00: 00: 00.01
执行计划
----------------------------------------------------------
Plan hash value: 1137212925
--------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%
cpu)| Time |
--------------------------------------------------------------------------------
| 0 | UPDATE STATEMENT | | 5 | 165 | 20 (30)| 00:00:01 |
| 1 | UPDATE | TA | | | | |
|* 2 | HASH JOIN SEMI | | 5 | 165 | 5 (20)| 00:00:01 |
| 3 | TABLE ACCESS FULL | TA | 5 | 100 | 2 (0)| 00:00:01 |
| 4 | VIEW | VW_SQ_1 | 4 | 52 | 2 (0)| 00:00:01 |
| 5 | TABLE ACCESS FULL| TB | 4 | 52 | 2 (0)| 00:00:01 |
|* 6 | TABLE ACCESS FULL | TB | 1 | 26 | 2 (0)| 00:00:01 |
--------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - access("TA"."A"="ITEM_1")
6 - filter("TB"."A"=:B1)
Note
-----
- dynamic sampling used for this statement (level=2)
统计信息
----------------------------------------------------------
0 recursive calls
4 db block gets
23 consistent gets
0 physical reads
1004 redo size
840 bytes sent via
sql*Net to client
856 bytes received via
sql*Net from client
3
sql*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
4 rows processed
sql> update ta set ta.b=(select tb.b from tb where ta.a=tb.a) where ta.a= (select tb.a from tb where ta.a=tb.a);
已更新4行。
已用时间: 00: 00: 00.00
执行计划
----------------------------------------------------------
Plan hash value: 3571861550
----------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%
cpu)| Time |
----------------------------------------------------------------------------
| 0 | UPDATE STATEMENT | | 1 | 20 | 7 (15)| 00:00:01 |
| 1 | UPDATE | TA | | | | |
|* 2 | FILTER | | | | | |
| 3 | TABLE ACCESS FULL| TA | 5 | 100 | 2 (0)| 00:00:01 |
|* 4 | TABLE ACCESS FULL| TB | 1 | 13 | 2 (0)| 00:00:01 |
|* 5 | TABLE ACCESS FULL | TB | 1 | 26 | 2 (0)| 00:00:01 |
----------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - filter("TA"."A"= (SELECT "TB"."A" FROM "TB" "TB" WHERE
"TB"."A"=:B1))
4 - filter("TB"."A"=:B1)
5 - filter("TB"."A"=:B1)
Note
-----
- dynamic sampling used for this statement (level=2)
统计信息
----------------------------------------------------------
11 recursive calls
1 db block gets
53 consistent gets
0 physical reads
588 redo size
840 bytes sent via
sql*Net to client
858 bytes received via
sql*Net from client
3
sql*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
4 rows processed 如果 create unique index tb_a_uidx on tb(a); [Copy to clipboard] [ - ] CODE:
sql> update (select ta.b tab1,tb.b tbb from ta,tb where ta.a=tb.a) set tab1=tbb;
已更新4行。
已用时间: 00: 00: 00.01
执行计划
----------------------------------------------------------
Plan hash value: 176165
5026
----------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%
cpu)| Time |
----------------------------------------------------------------------------
| 0 | UPDATE STATEMENT | | 4 | 184 | 5 (20)| 00:00:01 |
| 1 | UPDATE | TA | | | | |
|* 2 | HASH JOIN | | 4 | 184 | 5 (20)| 00:00:01 |
| 3 | TABLE ACCESS FULL| TB | 4 | 104 | 2 (0)| 00:00:01 |
| 4 | TABLE ACCESS FULL| TA | 5 | 100 | 2 (0)| 00:00:01 |
----------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - access("TA"."A"="TB"."A")
Note
-----
- dynamic sampling used for this statement (level=2)
统计信息
----------------------------------------------------------
8 recursive calls
4 db block gets
17 consistent gets
0 physical reads
1004 redo size
840 bytes sent via
sql*Net to client
827 bytes received via
sql*Net from client
3
sql*Net roundtrips to/from client
3 sorts (memory)
0 sorts (disk)
4 rows processed
原文链接：https://www.f2er.com/mssql/63916.html
