Question

我希望使用提供的建议here和here

向表中添加新列

本质上，我希望自动填充（fields_in_orig_table），而不必手动输入它们（有很多列，这会从表到表更改）：

CREATE TABLE games_new LIKE games_orig;
ALTER TABLE games_new ADD COLUMN location varchar(256);
INSERT INTO games_new (fields_in_orig_table) SELECT * FROM games_orig;
RENAME TABLE games_orig TO games_old, games_new TO games_orig;
DROP TABLE games_old;

我的想法是：

CREATE TABLE games_new LIKE games_orig;
ALTER TABLE  games_new ADD COLUMN version varchar(256);
INSERT INTO  games_new 

          (SELECT CONCAT(GROUP_CONCAT(column_name ORDER BY ordinal_position 
           SEPARATOR " ,  "), " ") AS columns
           FROM information_schema.columns
           WHERE table_schema = 'games' AND table_name = 'games_orig' ) 

SELECT * FROM games_orig;
RENAME TABLE games_orig TO games_old, games_new TO games_orig;
DROP TABLE games_old;

这给了我语法错误（在Select concat ....附近）。

获取逗号分隔列列表的原始语法是：

SELECT CONCAT("'", GROUP_CONCAT(column_name ORDER BY ordinal_position SEPARATOR "', '"), "'") AS columns
FROM information_schema.columns
WHERE table_schema = 'db_name' AND table_name = 'tbl_name'

在我的查询中，我删除了额外的引号，因为我认为我的查询不需要引号作为列列表的一部分。

我在这里做错了什么？谁能提供帮助呢？

Answer 1

INSERT INTO  games_new 

VALUES (SELECT CONCAT....

Answer 2

在表格中插入值时，请使用INSERT INTO tablename VALUES (fields)代替INSERT INTO tablename SET(fields)。

CREATE TABLE games_new LIKE games_orig;
ALTER TABLE  games_new ADD COLUMN version varchar(256);
INSERT INTO  games_new 
          VALUES
          (SELECT CONCAT(GROUP_CONCAT(column_name ORDER BY ordinal_position 
           SEPARATOR ' , '), ' ') AS columns
           FROM information_schema.columns
           WHERE table_schema = 'games' AND table_name = 'games_orig' ) 

SELECT * FROM games_orig;
RENAME TABLE games_orig TO games_old, games_new TO games_orig;
DROP TABLE games_old;

Answer 3

您尚未指定要插入的列，因为嵌套查询仅返回1个值

INSERT INTO games_new (column_name_u_want_to_insert_value_into) 
SELECT   cast(concat(group_concat(column_name ORDER BY ordinal_position SEPARATOR " , "), " ") AS CHAR) AS columns
FROM     information_schema.columns 
WHERE    table_name = 'games_orig';

另外，如果你一起运行所有语句，也要为插入查询添加分号（;）

ALTER TABLE ADD COLUMN和自动COLUMNS列表

3 个答案: