Methods oracle and mysql multi-table delete a lot of data, many of which were not proven, you are likely to have been misled by erroneous information, the following two tables I deleted to mysql data, for example, to give to this notice a little, I created two tables in mysql, are user table and the state table, as shown below.
User table users:
National Table country, as shown:
When you see these two mysql table, you must think multi-table data to delete such statements are, in fact, this is wrong! ,as follows.
delete from users u,country c where u.id = c.userId and u.id = 20
mysql multi-table delete statement reported by the above sql syntax syntax error, given as follows.
[SQL]
delete from users u,country c where u.id = c.userId and u.id = 20
[Err] 1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'u,country c where u.id = c.userId and u.id = 20' at line 1
Multi mysql delete data table provided with correct way to remove the connection, the following two statements, an optionally.
//语句一 delete u,c from users u INNER JOIN country c on u.id = c.userId and u.id = 20 //语句二 delete u,c from users u INNER JOIN country c where u.id = c.userId and u.id = 10
This time you'll think, oracle delete data able to use multi-table above these two statements? The answer is: No! , It will be reported as an error.
"ORA-00933: SQL command not properly use"
Description oracle use the above two statements are not multi-table delete data, and multi-table delete data that oracle how to write it? Command is as follows.
// the Oracle can only perform separate the Delete from the Users the WHERE users.id = 20 the Delete from Country the WHERE country.userId = 20
In oracle can not delete the associated multi-table, which may be followed by security mechanisms related to oracle database, you can only put the above statement into two sql statements to perform can achieve multi-table delete oracle.
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