db2的常用操作

db2的常用操作

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创建表

DROP TABLE T_PATRON_INFO;

CREATE TABLE T_PATRON_INFO (
  USER_ID        INTEGER       GENERATED ALWAYS AS IDENTITY (START WITH 1 INCREMENT BY 1),
  UAER_NM	     VARCHAR(16)   NOT NULL DEFAULT ,
  ROW_CRT_TS	 TIMESTAMP 	   NOT NULL DEFAULT ,
  primary key(USER_ID)
)

sequence操作
创建sequence

CREATE SEQUENCE  T_PATRON_INFO_SEQUENCE  AS INT START WITH 1 INCREMENT BY 1 MINVALUE 1 NO MAXVALUE NO CYCLE NO CACHE ORDER;

CREATE SEQUENCE  T_PATRON_INFO_SEQUENCE1  START WITH 1 INCREMENT BY 1 NOMAXVALUE NOCYCLE CACHE 24;

查询sequence （获取当前值用prevval，下一个值用nextval）

select nextval for T_PATRON_INFO_SEQUENCE from sysibm.sysdummy1

select nextval for T_PATRON_INFO_SEQUENCE from T_PATRON_INFO;

删除sequence

 DROP SEQUENCE T_PATRON_INFO_SEQUENCE   ;

操作操作时间戳，TIMESTAMP（db2插入时间（date）类型）

下面的时间也可以定义为 2016-10-26 22：22：22
也可以用函数代替 current timestamp

INSERT INTO T_PATRON_INFO(UAER_NM,ROW_CRT_TS) values ('patronli','2016-10-26');

增加字段

ALTER TABLE t_patron_info ADD COLUMN sp_cd CHAR(6);

修改字段

ALTER TABLE t_patron_info ALTER sp_cd SET DATA TYPE DECIMAL(3);

db2根据日期分组（日期转字符）（但是在版本较低的db2中不支持to-char）

to_char(row_crt_ts,'YYYY-MM') as transDate,count(0) as num from T_patronli_info  group by to_char(row_crt_ts,'YYYY-MM')

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