php MySQL删除多列
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MySQL Drop Multiple Columns
提问by Cory Nickerson
I'm trying to drop multiple columns, but having some trouble. The syntax below works when I do ALTER TABLEand ADDwith multiple values in the brackets ()but it doesn't work with DROP COLUMN. Am I using the wrong syntax?
我正在尝试删除多个列，但遇到了一些麻烦。下面，当我做作品的语法ALTER TABLE和ADD用括号多个值()，但它不工作DROP COLUMN。我使用了错误的语法吗？
$table3 = "
ALTER TABLE $table3_name
DROP COLUMN (
user_firstname,
user_lastname,
user_address,
user_address2,
user_city,
user_state,
user_zip,
user_phone
);
";
回答by void
ALTER TABLE `tablename`
DROP `column1`,
DROP `column2`,
DROP `column3`;
回答by MANISH ZOPE
To drop multiple columns actual syntax is
删除多列的实际语法是
alter table tablename drop column col1, drop column col2 , drop column col3 ....
So for every column you need to specify "drop column" in Mysql 5.0.45. This is same as that of above answer. Just adding one point here. Alter table wont free up the actual space on the disk. So run optimize table on after running optimize table.
因此，对于每一列，您需要在 Mysql 5.0.45 中指定“删除列”。这与上面的答案相同。这里只加一分。更改表不会释放磁盘上的实际空间。所以在运行优化表之后运行优化表。
