我试图使用一个选择语句从某个MySQL表中获得除一个以外的所有列。有什么简单的方法吗?

编辑:在这个表格中有53列(不是我的设计)


当前回答

也许我有一个解决Jan Koritak指出的矛盾的方法

SELECT CONCAT('SELECT ',
( SELECT GROUP_CONCAT(t.col)
FROM
(
    SELECT CASE
    WHEN COLUMN_NAME = 'eid' THEN NULL
    ELSE COLUMN_NAME
    END AS col 
    FROM INFORMATION_SCHEMA.COLUMNS 
    WHERE TABLE_NAME = 'employee' AND TABLE_SCHEMA = 'test'
) t
WHERE t.col IS NOT NULL) ,
' FROM employee' );

表:

SELECT table_name,column_name 
FROM INFORMATION_SCHEMA.COLUMNS 
WHERE TABLE_NAME = 'employee' AND TABLE_SCHEMA = 'test'

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

table_name  column_name
employee    eid
employee    name_eid
employee    sal

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

查询结果:

'SELECT name_eid,sal FROM employee'

其他回答

这个问题是关于MySQL的,但我仍然认为值得一提的是,至少谷歌BigQuery和H2原生支持* EXCEPT语法。

SELECT * FROM actor

生产:

|actor_id|first_name|last_name   |last_update            |
|--------|----------|------------|-----------------------|
|1       |PENELOPE  |GUINESS     |2006-02-15 04:34:33.000|
|2       |NICK      |WAHLBERG    |2006-02-15 04:34:33.000|
|3       |ED        |CHASE       |2006-02-15 04:34:33.000|

SELECT * EXCEPT (last_update) FROM actor

生产:

|actor_id|first_name|last_name   |
|--------|----------|------------|
|1       |PENELOPE  |GUINESS     |
|2       |NICK      |WAHLBERG    |
|3       |ED        |CHASE       |

也许,MySQL的未来版本也会支持这种语法?

如果您不想选择的列中有大量数据,并且由于速度问题而不想包括它,并且您经常选择其他列,那么我建议您使用一个通常不选择的字段创建一个新表,并从原始表中删除该字段。当实际需要额外字段时,将表连接起来。

我同意列出所有列的“简单”解决方案,但这可能会造成负担,而且打字错误可能会浪费大量时间。我使用“getTableColumns”函数检索适合粘贴到查询中的列的名称。然后我要做的就是删除我不想要的。

CREATE FUNCTION `getTableColumns`(tablename varchar(100)) 
          RETURNS varchar(5000) CHARSET latin1
BEGIN
  DECLARE done INT DEFAULT 0;
  DECLARE res  VARCHAR(5000) DEFAULT "";

  DECLARE col  VARCHAR(200);
  DECLARE cur1 CURSOR FOR 
    select COLUMN_NAME from information_schema.columns 
    where TABLE_NAME=@table AND TABLE_SCHEMA="yourdatabase" ORDER BY ORDINAL_POSITION;
  DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
  OPEN cur1;
  REPEAT
       FETCH cur1 INTO col;
       IF NOT done THEN 
          set res = CONCAT(res,IF(LENGTH(res)>0,",",""),col);
       END IF;
    UNTIL done END REPEAT;
  CLOSE cur1;
  RETURN res;

您的结果返回一个以逗号分隔的字符串,例如…

col1, col2 col3 col4, ... col53

如果你想排除一个字段的值,例如安全问题/敏感信息,你可以检索该列为空。

e.g.

SELECT *, NULL AS salary FROM users

据我所知,没有。你可以这样做:

SELECT col1, col2, col3, col4 FROM tbl

并手动选择所需的列。然而,如果你想要很多列,那么你可能只需要做一个:

SELECT * FROM tbl 

忽略你不想要的。

针对你的特殊情况,我建议:

SELECT * FROM tbl

除非你只想要几列。如果你只想要四列,那么:

SELECT col3, col6, col45, col 52 FROM tbl

这很好,但如果您想要50个列,那么任何使查询变得(太?)难以阅读的代码。