使用MySQL用户定义变量连接UPDATE语句上的表名
我正在尝试为使用MySQL用户定义变量连接UPDATE语句上的表名,mysql,sql,concat,Mysql,Sql,Concat,我正在尝试为UPDATE语句设置表名前缀。我必须在多个数据库上运行这个UPDATE语句几十次,每个数据库都有不同的表前缀 下面的代码不起作用,但这正是我试图实现的想法 SET @prefix = 'prefix_'; SET @old = "old_value"; SET @new = "new_value"; UPDATE CONCAT(@prefix, 'table1') SET some_field = REPLACE(some_field, @old, @new); UPDATE CON
UPDATE
语句设置表名前缀。我必须在多个数据库上运行这个UPDATE
语句几十次,每个数据库都有不同的表前缀
下面的代码不起作用,但这正是我试图实现的想法
SET @prefix = 'prefix_';
SET @old = "old_value";
SET @new = "new_value";
UPDATE CONCAT(@prefix, 'table1') SET some_field = REPLACE(some_field, @old, @new);
UPDATE CONCAT(@prefix, 'table2') SET some_field = REPLACE(some_field, @old, @new);
UPDATE CONCAT(@prefix, 'table3') SET some_field = REPLACE(some_field, @old, @new);
手动编写的将是
UPDATE prefix_table1 SET some_field = REPLACE(some_field, 'old_value', 'new_value');
UPDATE prefix_table2 SET some_field = REPLACE(some_field, 'old_value', 'new_value');
UPDATE prefix_table3 SET some_field = REPLACE(some_field, 'old_value', 'new_value');
在此基础上使用
动态SQL
SET @prefix = 'prefix_';
SET @old = "old_value";
SET @new = "new_value";
SET @sql1 = CONCAT('UPDATE ', @prefix, 'table1 SET some_field = REPLACE(some_field,?,?)');
SET @sql2 = CONCAT('UPDATE ', @prefix, 'table2 SET some_field = REPLACE(some_field,?,?)');
SET @sql3 = CONCAT('UPDATE ', @prefix, 'table3 SET some_field = REPLACE(some_field,?,?)');
PREPARE stmt1 FROM @sql1;
PREPARE stmt2 FROM @sql2;
PREPARE stmt3 FROM @sql3;
EXECUTE stmt1 USING @old, @new;
EXECUTE stmt2 USING @old, @new;
EXECUTE stmt3 USING @old, @new;
DEALLOCATE PREPARE stmt1;
DEALLOCATE PREPARE stmt2;
DEALLOCATE PREPARE stmt3;
动态SQL
SET @prefix = 'prefix_';
SET @old = "old_value";
SET @new = "new_value";
SET @sql1 = CONCAT('UPDATE ', @prefix, 'table1 SET some_field = REPLACE(some_field,?,?)');
SET @sql2 = CONCAT('UPDATE ', @prefix, 'table2 SET some_field = REPLACE(some_field,?,?)');
SET @sql3 = CONCAT('UPDATE ', @prefix, 'table3 SET some_field = REPLACE(some_field,?,?)');
PREPARE stmt1 FROM @sql1;
PREPARE stmt2 FROM @sql2;
PREPARE stmt3 FROM @sql3;
EXECUTE stmt1 USING @old, @new;
EXECUTE stmt2 USING @old, @new;
EXECUTE stmt3 USING @old, @new;
DEALLOCATE PREPARE stmt1;
DEALLOCATE PREPARE stmt2;
DEALLOCATE PREPARE stmt3;