mysql 增加修改字段类型及删除字段类型
MySQL添加字段:
altertable`user_movement_log` AddcolumnGatewayIdintnotnulldefault0AFTER`Regionid`(在哪个字段后面添加)
删除字段:
altertable`user_movement_log`dropcolumnGatewayid
调整字段顺序:
ALTERTABLE`user_movement_log`CHANGE`GatewayId``GatewayId`intnotnulldefault0AFTERRegionID //主键 altertabletabelnameaddnew_field_idint(5)unsigneddefault0notnullauto_increment,addprimarykey(new_field_id);//增加一个新列 altertablet2adddtimestamp; altertableinfosaddextinyintnotnulldefault'0';//删除列 altertablet2dropcolumnc;//重命名列 altertablet1changeabinteger; //改变列的类型 altertablet1changebbbigintnotnull; altertableinfoschangelistlisttinyintnotnulldefault'0'; //重命名表 altertablet1renamet2;加索引 mysql>altertabletablenamechangedepnodepnoint(5)notnull; mysql>altertabletablenameaddindex索引名(字段名1[,字段名2…]); mysql>altertabletablenameaddindexemp_name(name);加主关键字的索引 mysql>altertabletablenameaddprimarykey(id);加唯一限制条件的索引 mysql>altertabletablenameadduniqueemp_name2(cardnumber);删除某个索引 mysql>altertabletablenamedropindexemp_name;修改表:
增加字段:
mysql>ALTERTABLEtable_nameADDfield_namefield_type;修改原字段名称及类型: mysql>ALTERTABLEtable_nameCHANGEold_field_namenew_field_namefield_type;删除字段: mysql>ALTERTABLEtable_nameDROPfield_name;