甲骨文。 如果第一条语句存在记录，则忽略第二条

Question

I'm having a question how to resolve my problem.

I have procedure where inside i'm having this SELECT inside LEFT OUTER JOIN witch are returning me some values:

SELECT * FROM database1 data1
                        JOIN database2 data2 ON data2.id = data1.attr_id
                        JOIN database3 data3 ON data3.attr_id = data2.id
                        JOIN database4 data4 ON data4.objt_attr_id = data3.id
                        JOIN database5 data5 ON data5.stya_id = data4.id
                            AND data5.value = 1
        JOIN database6 data6 ON data6.id = data5.sero_id
        JOIN database7 data7 ON srv.id = data6.srv_id
        JOIN database8 data8 ON data8.code IN ('CALC1','CALC2')
        WHERE data1.ordet_id IN (data8.id)

As you can see he is looking for CALC1 and CALC2 And then search by their ID's in data1.ordet_id . Naturally, he return me 2 entries witch is not correct.

How to make the check. When script will find record with CALC1 , then he skips the check on CALC2 , so the script is returning only 1 record by CALC1 (not like now for both). And vice versa, if by CALC1 record wasn't found, he check the CALC2

Answer 1

I think you can take advantage of the analytical function row_number as following:

select * from
(SELECT data1.*, data2.*, .. data8.*, 
        row_number() over (partition by data1.ordet_id order by data8.code ) as rn 
        FROM database1 data1
        JOIN database2 data2 ON data2.id = data1.attr_id
        JOIN database3 data3 ON data3.attr_id = data2.id
        JOIN database4 data4 ON data4.objt_attr_id = data3.id
        JOIN database5 data5 ON data5.stya_id = data4.id
                            AND data5.value = 1
        JOIN database6 data6 ON data6.id = data5.sero_id
        JOIN database7 data7 ON srv.id = data6.srv_id
        JOIN database8 data8 ON data8.code IN ('CALC1','CALC2')
        WHERE data1.ordet_id IN (data8.id))
where rn = 1

-- Update

As per your below comment, You can also use NOT EXISTS and combination of CASE..WHEN as following:

SELECT  *
FROM
    DATABASE1 DATA1
    JOIN DATABASE2 DATA2 ON DATA2.ID = DATA1.ATTR_ID
    JOIN DATABASE3 DATA3 ON DATA3.ATTR_ID = DATA2.ID
    JOIN DATABASE4 DATA4 ON DATA4.OBJT_ATTR_ID = DATA3.ID
    JOIN DATABASE5 DATA5 ON DATA5.STYA_ID = DATA4.ID
                            AND DATA5.VALUE = 1
    JOIN DATABASE6 DATA6 ON DATA6.ID = DATA5.SERO_ID
    JOIN DATABASE7 DATA7 ON SRV.ID = DATA6.SRV_ID
    JOIN DATABASE8 DATA8 ON DATA8.CODE IN (
        'CALC1',
        'CALC2'
    )
WHERE
    CASE
        WHEN DATA8.CODE = 'CALC1' THEN DATA1.ORDET_ID
        WHEN DATA8.CODE = 'CALC2' THEN CASE
            WHEN NOT EXISTS (
                SELECT 1 FROM
                    DATABASE8 D8
                WHERE DATA1.ORDET_ID = D8.ID
                  AND D8.CODE = 'CALC1'
            ) THEN DATA1.ORDET_ID
        END
    END = DATA8.ID

Cheers!!

Answer 2

Join twice with OUTER JOIN (ie you loose no record if the matched code doesn't exists, but you will not duplicate the result ) and the get the priorized code with COALESCE from the first or second join.

SELECT 
   data1.ordet_id ,
   COALESCE(data81.code, data82.code) code
FROM data1.ordet_id 
LEFT OUTER JOIN data81 ON data1.ordet_id = data81.id and data81.code = 'CALC1'
LEFT OUTER JOIN data82 ON data1.ordet_id = data82.id and data82.code = 'CALC2'