Update updates across tables, update updates across tables

Update updates across tables, update updates across tables

Sometimes we may need to update data between multiple tables. We can use this statement

UPDATE table1,table2 SET table1.column=table2.column, table1.column1=table2.column1WHERE table1.column3=table2.column3

Update data between two tables

Should I use SQL statements?

Update table1 set count = table2.count from table2 where table2.tid = table1.id

In this way, Table 1 can be updated.

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This is already the best method.

And the efficiency is very high. This is to directly connect two tables to update data.

Cross-Table update using the update keyword in oracle 10 GB

1. update emp A, emp2 B set B. comm = A. comm where B. empno = A. empno;
2. update emp2 B set B. comm = (select A. comm emp A where A. empno = B. empno group by A. comm );
If no group by is added, an error is returned if a duplicate value exists.
3. Save All IDS as a file or specify the id
Spoll id.txt
Select empno from emp;
Spool off

Write a shell
#! /Bin/sh
Cid = $1
If [-z "$1"]; then
Echo "Usage: $0 id.txt"
Exit 1;
Fi
For id in 'cat id.txt '; do
Echo-e "update emp2 B set B. comm = (select A. comm from emp A where A. empno = '$ id ')
Where B. id = '$ id ';"
Done | sqlplus-s 'user/123456'