Sql 基于选择查询更新记录

我有一张表1：

u_a_id  d_c_s   c_nm    c_seq   r_c_p
1       908     Test1   1       20
10      908     Test1   1       21
11      908     Test1   1       12
12759   908     Test1   1       31
12759   908     Test1   1       32
12861   878     Test2   1       43
12861   878     Test2   1       44

我还有一张表2：

d_c_s   c_nm    c_seq   n_min_d_c_s     n_min_c_nm
908     Test1   1       12001           Test1, First
878     Test2   1       12002           Test2, First

我需要更新表1==>

表1.c_nm=表2.n_min_c_nm 表1.d_c_s=表2.n_min_d_c_s 要更新的条件是：

仅记录u_a_id、d_c_s、c_seq的计数大于1的情况-从表1中选择u_a_id、d_c_s、c_nm、c_seq、count*cnt，其中c_nm不在“VOID”中，按u a_id、d_c_s、c_nm、c_seq分组计数大于1； 表1.d_c_s=表2.d_c_s 表1.c_纳米=表2.c_纳米 表1.c_seq=表2.c_seq 使用r_c_p的最小值 输出如下所示：

u_a_id  d_c_s   c_nm            c_seq   r_c_p
1       908     Test1           1       20
10      908     Test1           1       21
11      908     Test1           1       12
12759   12001   Test1, First    1       31
12759   908     Test1           1       32
12861   12002   Test2, First    1       43
12861   878     Test2           1       44

创建更新/合并查询的最佳方法是什么

DBFIDDLE演示-

您可以使用MERGE语句进行以下操作：

MERGE INTO TABLE1 T1 
USING (
       SELECT
           MIN(TI1.R_C_P) AS R_C_P,
           TI1.U_A_ID,
           TI1.D_C_S,
           TI1.C_NM,
           TI1.C_SEQ,
           TI2.N_MIN_C_NM,
           TI2.N_MIN_D_C_S
       FROM
           TABLE1 TI1
           JOIN TABLE2 TI2 
           ON ( TI1.D_C_S = TI2.D_C_S
                AND TI1.C_NM = TI2.C_NM
                AND TI1.C_SEQ = TI2.C_SEQ
                AND TI1.C_NM NOT IN (
               'VOID',
               'WRONG'
           ) )
       GROUP BY
           TI1.U_A_ID,
           TI1.D_C_S,
           TI1.C_NM,
           TI1.C_SEQ,
           TI2.N_MIN_C_NM,
           TI2.N_MIN_D_C_S
       HAVING
           COUNT(1) > 1
   )
T2 ON ( T1.C_SEQ = T2.C_SEQ
        AND T1.R_C_P = T2.R_C_P )
WHEN MATCHED THEN 
UPDATE 
SET T1.C_NM = T2.N_MIN_C_NM,
T1.D_C_S = T2.N_MIN_D_C_S
WHERE
    T1.D_C_S = T2.D_C_S
    AND T1.C_NM = T2.C_NM 
    AND T1.U_A_ID = T2.U_A_ID -- ADDED THIS CONDITION
-- WHERE CONDITION IS USED AS IT CAN NOT BE USED INSIDE ON CLAUSE
-- TO AVOID ERROR : ORA-38104: Columns referenced in the ON Clause cannot be updated

---

干杯

如果我将第一行的R_C_p更改为43，则会给出错误的输出-是的，我试图在WHERE子句中放置一些唯一的列。现在我已经在它里面放了U_A_ID，这样它就可以识别正确的记录了。如果表1中有PK，则只使用WHERE子句中的该列。。请参阅更新的答案和更新的fiddler链接。这一行是T2.C_SEQ=T2.C_SEQ上的T2吗？正确吗？哦。。不，那是不对的。现在已更正。是否会因此导致任何问题？如果我将第一行的r_c_p更改为43，则输出错误-不清楚这是否是一个要求。看起来你找到了一个满足你需要的答案，所以我不打算重做了。

MERGE INTO TABLE1 T1 
USING (
       SELECT
           MIN(TI1.R_C_P) AS R_C_P,
           TI1.U_A_ID,
           TI1.D_C_S,
           TI1.C_NM,
           TI1.C_SEQ,
           TI2.N_MIN_C_NM,
           TI2.N_MIN_D_C_S
       FROM
           TABLE1 TI1
           JOIN TABLE2 TI2 
           ON ( TI1.D_C_S = TI2.D_C_S
                AND TI1.C_NM = TI2.C_NM
                AND TI1.C_SEQ = TI2.C_SEQ
                AND TI1.C_NM NOT IN (
               'VOID',
               'WRONG'
           ) )
       GROUP BY
           TI1.U_A_ID,
           TI1.D_C_S,
           TI1.C_NM,
           TI1.C_SEQ,
           TI2.N_MIN_C_NM,
           TI2.N_MIN_D_C_S
       HAVING
           COUNT(1) > 1
   )
T2 ON ( T1.C_SEQ = T2.C_SEQ
        AND T1.R_C_P = T2.R_C_P )
WHEN MATCHED THEN 
UPDATE 
SET T1.C_NM = T2.N_MIN_C_NM,
T1.D_C_S = T2.N_MIN_D_C_S
WHERE
    T1.D_C_S = T2.D_C_S
    AND T1.C_NM = T2.C_NM 
    AND T1.U_A_ID = T2.U_A_ID -- ADDED THIS CONDITION
-- WHERE CONDITION IS USED AS IT CAN NOT BE USED INSIDE ON CLAUSE
-- TO AVOID ERROR : ORA-38104: Columns referenced in the ON Clause cannot be updated