通过mysql查询将1列复制到另一列

Question

我有以下表的mysql数据库...

| id | amount | tax |
+----+--------+-----+
|  1 | 500    |     |
+----+--------+-----+
|  2 | 100    |     |
+----+--------+-----+

我必须删除金额列,但在此之前我想将金额行的所有数据从金额行转移到税行.怎么用mysql查询呢？请帮忙.

Answer 1

UPDATE mytable SET tax = amount

你可以删除它之后

ALTER TABLE mytable DROP COLUMN amount; 

Answer 2

update TABLE_NAME set tax=amount;

会做。