mysql-modifying field types and modifying field names

article turned from: 79354136

MySQL Modify field type:--can modify field type, type length, default value, comment--make a change to a fieldALTER  TABLETable name MODIFYCOLUMNField name new data type new type length new default value new comment;--column can be omittedAlter  TableTable1 ModifycolumnColumn1decimal(Ten,1)DEFAULT NULLCOMMENT'Notes';--Normal, can modify field type, type length, default value, commentmysql Modify field name:ALTER  TABLETable name change old field name new data type new field name; Alter  TableTable1 Change Column1 Column1varchar( -)DEFAULT 1.2COMMENT'Notes';--Normal, the field name does not change, you can modify the field type, type length, default value, commentAlter  TableTable1 Change Column1 Column2decimal(Ten,1)DEFAULT NULLCOMMENT'Notes' --Normal, can modify field name, field type, type length, default value, commentAlter  TableTable1 Change Column2 column1decimal(Ten,1)DEFAULT NULLCOMMENT'Notes' --Normal, can modify field name, field type, type length, default value, commentAlter  TableTable1 change Column1 column2;--Error

Change Note:
The field type after the field must be added, regardless of whether the field type or field name is modified, the default value is null if not passed by default

mysql-modifying field types and modifying field names