db2语法小知识

修改一列为自增长型：

ALTER TABLE TBL_QB_BATCH_ACCOUNT ALTER COLUMN ID SET DATA TYPE INTEGER;

ALTER TABLE TBL_QB_BATCH_ACCOUNT ALTER COLUMN ID SET GENERATED ALWAYS AS IDENTITY( START WITH 1,INCREMENT BY 1,NO CACHE);

修改一列的长度：

alter table tbl_qb_merch_qrcode  alter column serurl set data type  VARCHAR(255);

删除索引：
DROP INDEX IDX_QB_RISK_PARAM;

创建唯一索引：

CREATE UNIQUE INDEX IDX_QB_RISK_PARAM ON TBL_QB_RISK_PARAM (USER_TYPE, ORDER_CLASS, BIZ_TYPE, SUB_BIZ_TYPE, USER_LEVEL, MERCH_ID, PAYTYPE );

查看表的结构：

db2 describe indexes for table MIBS.tbl_qb_risk_param show detail;

查看注释：
select t.Remarks as 注释,t.* from syscat.COLUMNS t where tabschema='MIBS01' and tabname=upper('tbl_gw_txninfo');

把时间戳格式转换为varchar格式：

to_char( FM_CREATETIME,'YYYYMMDDhh24miss')

修改表名：

RENAME TABLE atest_course TO  atest