SELECT
    REPLACE(DEPT_NAME, "課", "グループ")
FROM
    TBL_DEPT
WHERE
    VALID_FLG = 1;

UPDATE TBL_DEPT
    SET DEPT_NAME = REPLACE(DEPT_NAME, "課", "グループ")
WHERE
    VALID_FLG = 1;
    
SELECT *
FROM TBL_DEPT;