Mainframe COBOL db2 delete program

问题

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DB2/Cursor program working in cobol

回答1:

This should be a 2 step process. First identify the records that are to be deleted and then delete those records in the 2nd step. I think, you'll Not be able to delete the records from the same table you are fetching, that's why 2 steps.

Step 1:

Select Concat(A.ClientId, A.PhoneNumber, A.Timestamp) from MyTable A
 Where Concat(A.ClientId, A.PhoneNumber, A.Timestamp)
Not IN (Select Concat(B.ClientId, B.PhoneNumber, Min(B.Timestamp))
    from MyTable B
    Group by B.ClientId, B.PhoneNumber);

Step 2:

Delete from MyTable
 Where Concat(A.ClientId, A.PhoneNumber, A.Timestamp) IN (all the values you got from Step1);

You can run step 1, create a dataset to get all the values and use that dataset in step 2. If you are running dynamic then a cut paste will do, else you'll have to modify the dataset using SORT to create a query out of it. That will be another Step in the middle of step 1 and 2.

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来源：https://stackoverflow.com/questions/47152124/mainframe-cobol-db2-delete-program