Question

我想将表A中的数据复制/更新到表B.表B还有一些额外的列。我尝试了以下选项。

1) `REPLACE INTO `B` (SHOW FIELDS FROM 'A') SELECT * FROM `A

2) `REPLACE INTO `B` 
     (SELECT `COLUMN_NAME` FROM `INFORMATION_SCHEMA`.`COLUMNS` 
              WHERE `TABLE_SCHEMA`='test1' AND `TABLE_NAME`='A') SELECT * FROM `A

但它会引发错误。你能帮助我如何用选择查询选择名字吗？

更新

3）正如Jerko所说，

我有两个表A（warehouse_id，long，lat）B（warehouse_id，long）

应用以下声明。

SET @query = CONCAT('REPLACE INTO `A` (SELECT  ', 
                     (SELECT GROUP_CONCAT(CONCAT('`',column_name, '`')) 
                      FROM information_schema.columns 
                      WHERE  `TABLE_SCHEMA`='test2' AND `table_name` = 'A'), 
                   ' FROM  `B`)');


PREPARE stmt FROM @query;
EXECUTE stmt;

这给了我错误

“＃1054 - '字段列表'中的未知列'lat'”

Answer 1

你不能像在尝试那样在mysql中动态地执行此操作。 MySQL期望直接提供列名列表，而不是从子查询中提供。

如果你想动态地这样做，你将不得不向上游退回到用于与MySQL交互的任何语言，例如PHP或Java。

Answer 2

你试过这个吗？

insert into B(col1, . . ., coln)
    select col1, . . ., coln
    from A;

即，列出A子句中select的字段。列出B列列表中insert的相应列。

如果您需要列列表，请从INFORMATION_SCHEMA.COLUMNS获取并剪切并粘贴到查询中。

Answer 3

试试这个

INSERT INTO B (field1,field2,...,fieldN) 
        SELECT (field1,field2,...,fieldN) FROM A

Answer 4

实际上有一种方法

SET @query = CONCAT('REPLACE INTO `A` (', 
                  (SELECT GROUP_CONCAT(CONCAT('`',column_name, '`')) 
                  FROM information_schema.columns 
                  WHERE  `TABLE_SCHEMA`='test1' AND `table_name` = 'A'
                  AND column_name IN (SELECT column_name FROM information_schema.columns WHERE table_schema = 'test1' AND table_name='B')) ,
                  ') (SELECT  ', 
                 (SELECT GROUP_CONCAT(CONCAT('`',column_name, '`')) 
                  FROM information_schema.columns 
                  WHERE  `TABLE_SCHEMA`='test1' AND `table_name` = 'A'
                  AND column_name IN (SELECT column_name FROM information_schema.columns WHERE table_schema = 'test1' AND table_name='B')), 
               ' FROM  `B`)');


PREPARE stmt FROM @query;
EXECUTE stmt;

如何在select语句中选择列名

4 个答案: