达梦数据库相关操作语句

“这个字段在 Java 对象里有，但数据库表里不存在，不要拼到 SQL 里。”

– 如果字段还不存在，直接 ADD

ALTER TABLE ABC.PERSON
ADD "NAME" NUMBER(1,0) DEFAULT 0;

– 给字段加注释

COMMENT ON COLUMN ABC.PERSON.NAME IS '状态，1待审计  2已审计';

–如果字段存在

ALTER TABLE ABC.PERSON
MODIFY PERSON NUMBER(1,0) DEFAULT 0;

–去重后列出 T_G_D_DEVICE 表所有列，并额外给 IP 做 DISTINCT

SELECT DISTINCT IP
FROM JYZYQ.T_G_D_DEVICE;

在达梦（DM）里要找出 两张表有哪些字段同名，最简单的是直接查系统字典视图 ALL_TAB_COLUMNS（或 USER_TAB_COLUMNS、DBA_TAB_COLUMNS）：

– 查当前用户下两张表的同名字段

SELECT COLUMN_NAMEFROM USER_TAB_COLUMNSWHERE TABLE_NAME IN ('T_G_D_WORK_ORDER', 'T_G_D_SESSION')   

– 表名大写GROUP BY COLUMN_NAMEHAVING COUNT(*) = 2; – 出现两次说明两张表都有

删除某列字段和该字段中数据的sql

ALTER TABLE JYZYQ.T_G_D_AUDIT_SESSION_LOG DROP COLUMN EVENT;

多表联合，stationName、User等用于前端输出

SELECT a.*, d.STATION as stationName, b.USER_NAME as User, b.CODE as operateCode, b.WORK_NUM as workNum,
c.TITLE as rTitle, c.DETAIL as Detail, e.SYS_NAME as jumrName, f.RESULT as Result,
j.J_ACCOUNT as jAccount
FROM T_G_D_AUDIT_SESSION_LOG a
LEFT JOIN J j on j.ID=a.SESSION_ID
LEFT JOIN B b on b.code = j.OPERATE_CODE
LEFT JOIN C c on b.NUM = c.NUM
LEFT JOIN D d on b.DEVICE_ID = d.ID
LEFT JOIN E e on e.LOGIN_NAME = j.JUMPSERVER_ACCOUNT
LEFT JOIN F f on f.SESSION_ID = a.SESSION_ID

查询某表的某字段

SELECT *
FROM ABC.PERSON
WHERE "ID" = '051d118bf10d4bc198ef6d77a4381c70';

查询某表的某字段并添加某字段值：

UPDATE ABC.PERSON
SET    OPERATE_CODE = 'CZ1921871948525350912'
WHERE  ID = '051d118bf10d4bc198ef6d77a4381c70';

查询某表的某字段并添加多个字段值

> UPDATE ABC.PERSON SET    OPERATE_CODE = 'qwer',
>        STATUS_CODE  = 'A1'          -- 改的字段/值 
>        WHERE  ID = '051d118bf10d4bc198ef6d77a4381c70';

commit，记住一定要点提交