How to add fields and comments to a table in sql

How to add fields and comments to a table in sql

1. Add fields:

alter table table name ADD field name type;

eg:

alter table sys_cwzd ADD SCCLLJ VARCHAR2(50);

2. Add remarks:

comment on column table name. Field name is 'remark name';

eg:

comment on column sys_cwzd.SCCLLJ is 'Upload material path';

Content extension:

Add a new field:

alter table bulletin add citycode varchar(6) not null default 0; # city code

1. Set the encoding when creating the database

create database test character set utf8;

2. Set the encoding when creating a table

create table test(id int primary key)DEFAULT charset=utf8;

3. Modify the database encoding

alter database test character set utf8;

4. Modify the default encoding of the table

alter table test character set utf8;
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  • Summary of MySQL's commonly used SQL statements for creating tables, adding fields, modifying fields, and adding indexes

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