Common SQL statement Oracle Database

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 'merchandising information table';
Comment on column tb_sell.XSPH is 'ticket sales numbers';
Comment on column tb_sell.SPBH is 'Product Number';
Comment on column tb_sell.SPMC is 'Product Name';
Comment on column tb_sell.SPJM is 'simple commodity code';
Comment on column tb_sell.SPLB is 'Product Category';
Comment on column tb_sell.TXM is '条形码';
Comment on column tb_sell.XSSL is 'sales';
Comment on column tb_sell.SPDJ is 'commodity price';
Comment on column tb_sell.XSSJ is 'selling time';

 2. Modify columns

ALTER TABLE statement is used to add an existing table, delete, or modify columns.

ALTER TABLE table_name MODIFY column_name datatype;