What are the types of fields that mysql can modify?

mysql modified field types include: 1. Add fields [alter table table1 (table name) add No_id (field name)]; 2. Modify field types [t1 (table name) alter column a (field name) ]; 3. Delete a field of a table [drop 'cpid'].

mysql modified field types are:

1, mysql modified field default value

alter table tb_mer_team_column drop constraint DF_tb_mer_team_column_columnOrder alter table tb_mer_team_column add constraint DF_tb_mer_team_column_columnOrder default 0 for columnOrder

2. mysql statement to add fields

alter table table1(表名)add No_id(字段名) char(12)(字段类型) t null | null   UNIQUE after '字符' 在制定字段后面添加

3. mysql changes field type

alter table t1(表名) alter column a(字段名) text(50)(字段类型)

4. mysql adds primary key field

alter table tb_mer_basInfo add constraint [PK_tb_merchantBasInfo] primary key ( merchantID)

5. mysql deletes a field of a table

alter table `lm_aclass` drop 'cpid'

Related learning recommendations: mysql video tutorial

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