问题
I'm a beginner in MySQL, and I accidentally created a table with a column named
(price decimal(2,2));
It needs to be decimal(4,2) to allow 4 digits. Since I've already created it, what is the easiest way to update that decimal value to decimal(4,2)? Or do I need to drop that column completely, and re-create it with the correct numbers?
I can't seem to get the syntax right.
Thank you very much.
回答1:
ALTER TABLE mytable MODIFY COLUMN mycolumn newtype
example:
ALTER TABLE YourTableNameHere MODIFY COLUMN YourColumnNameHere decimal(4,2)
回答2:
Just ALTER TABLE with the MODIFY command:
ALTER TABLE `table` MODIFY `price` DECIMAL(4,2)
This would allow for 2 decimals and 2 full numbers (up to 99.99). If you want 4 full numbers, use 6,2 instead (which would allow up to 9999.99).
回答3:
It's not a matter of 'UPDATE' it's a matter of changing your table's structure. For that, use ALTER TABLE with MODIFY clause:
ALTER TABLE YourTableName MODIFY COLUMN price DECIMAL(4,2);
sqlfiddle demo
回答4:
use CHANGE
ALTER TABLE table_name CHANGE OLD_COLUMN_NAME OLD_COLUMN_NAME datatype;
an example
ALTER TABLE table_name CHANGE price price decimal(4,2);
来源：https://stackoverflow.com/questions/19773164/mysql-how-do-i-update-the-decimal-column-to-allow-more-digits