Merge into用法

簡單的說就是，判斷表中有沒有符合on（）條件中的數據，有了就更新數據，沒有就插入數據。　　

有一個表T，有兩個字段a、b，咱們想在表T中作Insert/Update，若是條件知足，則更新T中b的值，不然在T中插入一條記錄。

 

merge into 目標表 a
 
using 源表 b
 
on(a.條件字段1=b.條件字段1 and a.條件字段2=b.條件字段2 ……)  
 
when matched then update set a.更新字段=b.字段
 
when  not matched then insert into a(字段1,字段2……)values(值1,值2……)

 

MERGE INTO USER UOR_0
USING (SELECT COUNT(1) AS ROW_COUNT
         FROM USER
        WHERE UOR_USER_ID = '2019052811'
          AND UOR_ORG_ID = '000002') UOR_1
ON (UOR_1.ROW_COUNT > 0)
WHEN MATCHED THEN
  UPDATE
     SET UOR_0.UDR_CREATE_USER_ID = 'admin',
         UOR_0.UDR_CREATE_DATE    = SYSDATE,
         UOR_0.UDR_UPDATE_USER_ID = 'admin',
         UOR_0.UDR_UPDATE_DATE    = SYSDATE,
         UOR_0.UDR_RECORD_STATUS  = '10'
   WHERE UOR_USER_ID = '2019052811'
     AND UOR_ORG_ID = '000002'
WHEN NOT MATCHED THEN
  INSERT
    (UOR_0.UOR_USER_ID,
     UOR_0.UOR_ORG_ID,
     UOR_0.UDR_CREATE_USER_ID,
     UOR_0.UDR_CREATE_DATE,
     UOR_0.UDR_UPDATE_USER_ID,
     UOR_0.UDR_UPDATE_DATE,
     UOR_0.UDR_RECORD_STATUS)
  VALUES
    ('2019052811', '000002', 'admin', SYSDATE, 'admin', SYSDATE, '10')