UPDATE  A
SET CORPORATION_NAME = (
    SELECT DISTINCT CORPORATION_NAME
    FROM (
        SELECT CONTRACT_NO, 
               COOP_SERVICE_TYPE, 
               CORPORATION_NAME, 
               PROJECT_NAME, 
               ROW_NUMBER() OVER (PARTITION BY CONTRACT_NO, COOP_SERVICE_TYPE ) AS SEQ
        FROM O_PLIS_PROC B
        WHERE B.BDHA_TX_DATE='2024-06-10' AND A.LM_CT1_NO = B.CONTRACT_NO
    ) B
    WHERE B.COOP_SERVICE_TYPE='01' AND B.SEQ = 1
)
WHERE LM_CT1_NO IN (
    SELECT  CONTRACT_NO
    FROM O_PLIS_PROC C
    WHERE C.CONTRACT_NO=A.LM_CT1_NO
    AND C.COOP_SERVICE_TYPE='01'
    AND C.BDHA_TX_DATE='2024-06-10'
);

CREATE INDEX TEST ON O_PLIS_PROC(
　　BDHA_TX_DATE,
　　COOP_SERVICE_TYPE,
　　CONTRACT_NO,
　　COOP_SERVICE_TYPE,
　　CORPORATION_NAME);

WITH O_PLIS_PROC as (
    SELECT 
           CONTRACT_NO,
           COOP_SERVICE_TYPE,
           CORPORATION_NAME
     FROM O_PLIS_PROC 
     WHERE BDHA_TX_DATE='2024-06-10' AND COOP_SERVICE_TYPE='01'
)
UPDATE A
SET CORPORATION_NAME = (
    SELECT  CORPORATION_NAME 
        FROM O_PLIS_PROC B 
    WHERE A.LM_CT1_NO = B.CONTRACT_NO  GROUP BY CONTRACT_NO, COOP_SERVICE_TYPE LIMIT 1 ) 
WHERE LM_CT1_NO IN (
    SELECT  CONTRACT_NO
    FROM O_PLIS_PROC C
    WHERE C.CONTRACT_NO=A.LM_CT1_NO
);