Conversion of merge statement to MYSQL using on duplicate key

问题

Please suggest how to convert this teradata statement in MYSQL. As we know mysql doesn't support merge statement. Below 2 tables are also being used in select query and we have multiple primary key in each table.

MERGE INTO XYZ USING (
            SELECT
                    ITRR.WORKFLOW_NAME WORKFLOW_NAME
            ,       ITRR.INSTANCE_NAME INSTANCE_NAME
            ,       MIN(ITRR.START_TIME) EARLIEST_START_TIME
            ,       ITRR.SUBJECT_AREA SUBJECT_AREA
            ,       'INFORMATICA' PLATFORM_NAME
            FROM
                    ABC IWRR
            ,       DEF ITRR
            WHERE
                    IWRR.WORKFLOW_RUN_ID = ITRR.WORKFLOW_RUN_ID
            AND     IWRR.USER_NAME IN ('xyz')
            AND     ITRR.RUN_STATUS_CODE <> 2
            GROUP BY
                    ITRR.WORKFLOW_NAME
            ,       ITRR.INSTANCE_NAME
            ,       ITRR.SUBJECT_AREA
    ) SRC
    ON
            XYZ.PARENT_JOB_NAME = SRC.WORKFLOW_NAME
    AND     XYZ.CHILD_JOB_NAME  = SRC.INSTANCE_NAME
    AND     XYZ.SANDBOX         = SRC.SUBJECT_AREA
    WHEN MATCHED THEN UPDATE SET FIRST_EXECUTION = SRC.EARLIEST_START_TIME
    WHEN NOT MATCHED THEN INSERT
    (
            PARENT_JOB_NAME
    ,       CHILD_JOB_NAME
    ,       FIRST_EXECUTION
    ,       SANDBOX
    ,       PLATFORM_NAME
    )VALUES
    (
            SRC.WORKFLOW_NAME
    ,       SRC.INSTANCE_NAME
    ,       SRC.EARLIEST_START_TIME
    ,       SRC.SUBJECT_AREA
    ,       SRC.PLATFORM_NAME
    );

I am trying below query but it is not working.

INSERT INTO XYZ (
                PARENT_JOB_NAME
,       CHILD_JOB_NAME
,       FIRST_EXECUTION
,       SANDBOX
,       PLATFORM_NAME
    )

       (SELECT
                ITRR.WORKFLOW_NAME WORKFLOW_NAME
        ,       ITRR.INSTANCE_NAME INSTANCE_NAME
        ,       MIN(ITRR.START_TIME) EARLIEST_START_TIME
        ,       ITRR.SUBJECT_AREA SUBJECT_AREA
        ,       'INFORMATICA' PLATFORM_NAME
        FROM
                ABC IWRR
        ,       DEF ITRR
        WHERE
                IWRR.WORKFLOW_RUN_ID = ITRR.WORKFLOW_RUN_ID
        AND     IWRR.USER_NAME IN ('XYZ')
        AND     ITRR.RUN_STATUS_CODE <> 2
        GROUP BY
                ITRR.WORKFLOW_NAME
        ,       ITRR.INSTANCE_NAME
        ,       ITRR.SUBJECT_AREA
 ) SRC
ON DUPLICATE KEY UPDATE
       FIRST_EXECUTION = SRC.EARLIEST_START_TIME

Primary key of XYZ = PARENT_JOB_NAME

Primary key of ABC= SUBJECT_ID

Primary key of DEF= SUBJECT_ID,WORKFLOW_ID,WORKFLOW_RUN_ID,WORKLET_RUN_ID,INSTANCE_ID,TASK_ID,START_TIME

回答1:

The correct syntax in MySQL is:

INSERT INTO XYZ (PARENT_JOB_NAME, CHILD_JOB_NAME, FIRST_EXECUTION, SANDBOX, PLATFORM_NAME)
    SELECT ITRR.WORKFLOW_NAME, ITRR.INSTANCE_NAME,
           MIN(ITRR.START_TIME), ITRR.SUBJECT_AREA, 'INFORMATICA'
    FROM ABC IWRR JOIN
         DEF ITRR
         ON IWRR.WORKFLOW_RUN_ID = ITRR.WORKFLOW_RUN_ID 
    WHERE IWRR.USER_NAME IN ('XYZ') AND
          ITRR.RUN_STATUS_CODE <> 2
    GROUP BY ITRR.WORKFLOW_NAME, ITRR.INSTANCE_NAME, ITRR.SUBJECT_AREA
ON DUPLICATE KEY UPDATE FIRST_EXECUTION = VALUES(FIRST_EXECUTION);

Note the use of proper, explicit, standard, readable JOIN syntax. Use it.

The major changes are

Fixing the archaic syntax.
Removing the parentheses are not needed for the select in an insert . . . select (although they are probably allowed).
Removing the table alias, which is definitely not allowed.
Fixing the on duplicate key statement.

回答2:

Believe the comment from @Akina is correct and that the primary key on the table XYZ is just incorrect.

The primary key on the XYZ table need to include these columns PARENT_JOB_NAME, CHILD_JOB_NAME and SANDBOX for the mysql INSERT ... ON DUPLICATE KEY statement to work correctly.

来源：https://stackoverflow.com/questions/61932378/conversion-of-merge-statement-to-mysql-using-on-duplicate-key

标签

mysql

sql

merge

teradata

teradata-sql-assistant