Use an user variable in a "INSERT ON" clause
I try to make a clean trigger with user-defined variables, so this is my code :
SET @target_bdd = 'trigger_second';
SET @trigger_name = 'account_copy';
SET @table_name = 'account';
SET @开发者_JS百科primary_key = 'id';
DROP TRIGGER IF EXISTS `@trigger_name`;
DELIMITER $$
CREATE TRIGGER `@trigger_name` AFTER INSERT
ON `@table_name`
FOR EACH ROW BEGIN
INSERT INTO `@target_bdd`.`@table_name`
SELECT * FROM `@table_name`
WHERE `@primary_key` = NEW.`@primary_key`;
END $$
DELIMITER ;
But I have this error :
ERROR 1064 (42000): 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 '@table_name
FOR EACH ROW BEGIN INSERT INTO `@target_bdd`.`@table_name` SELECT * ' at line 2
Why ? I tried with others quotes ('") but there's same error :(
With no quote :
ERROR 1064 (42000): 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 '@trigger_name AFTER INSERT ON @table_name FOR EACH ROW BEGIN INSERT INTO @target' at line 1
I try to declare an user-defined variable with SQL instructions like :
SET @sql = CONCAT(
'CREATE TRIGGER ',
@trigger_name,
' AFTER INSERT ON ',
@table_name,
' FOR EACH ROW BEGIN INSERT INTO ',
@target_bdd,
'.',
@table_name,
' SELECT * FROM ',
@table_name,
' WHERE ',
@primary_key,
' = NEW.',
@primary_key,
'; END'
);
PREPARE stmt FROM @sql;
EXECUTE stmt;
But I have an error 1295 (See in MySQL Documentation)
You can't use user variables for table names, columns etc in plain SQL. You can't also create a trigger in prepared statement (just like the error told you). Seems like there is currently no way to do what you want.
I must say that I've never used user defined variables before, but in testing it I found out you shouldn't quote them!
When you quote the `@vars` mysql will look for the literal '@vars'
field, in stead of the value that is stored in it.
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