Oracle数据库的常用SQL语句

1. Create table

create table tb_sell(
       XSPH varchar(20) NOT NULL,
       SPBH varchar(20) NOT NULL,
       SPMC varchar(20) NOT NULL,
       SPJM varchar(10),
       SPLB varchar(10),
       TXM varchar(20),
       XSSL number(10) NOT NULL,
       SPDJ number(10,2) NOT NULL,
       XSSJ date
       );
Comment on table tb_sell is '商品销售信息表';
Comment on column tb_sell.XSPH is '销售票号';
Comment on column tb_sell.SPBH is '商品编号';
Comment on column tb_sell.SPMC is '商品名称';
Comment on column tb_sell.SPJM is '商品简码';
Comment on column tb_sell.SPLB is '商品类别';
Comment on column tb_sell.TXM is '条形码';
Comment on column tb_sell.XSSL is '销售数量';
Comment on column tb_sell.SPDJ is '商品单价';
Comment on column tb_sell.XSSJ is '销售时间';

 2. 修改列

ALTER TABLE 语句用于在已有的表中添加、删除或修改列。

ALTER TABLE table_name MODIFY column_name datatype;

来源：https://www.cnblogs.com/htj10/p/12330133.html