[英]ALTER TABLE ADD COLUMN and automatic COLUMNS list
本质上,我希望自动填充(fields_in_orig_table) ,而不必手动输入(有很多列,并且表与表之间的变化):
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;
我的想法是这样的:
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)。
获取以逗号分隔的列列表的原始语法为:
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'
在查询中,我删除了多余的引号,因为我认为查询不需要引号作为列列表的一部分。
我在这做错了什么? 请问谁能帮忙?
INSERT INTO games_new
VALUES (SELECT CONCAT....
在表中插入值时,请使用INSERT INTO tablename VALUES (fields)
而不是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;
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,如果同时运行所有语句,请为插入查询添加分号(;)
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