how to pass null = null in the where clause












0















I have a bigquery select statement where in some cases, the where clauses show null = null



In the case of this statement:



select * from `db.ds.table1` t1
join `db.ds.table2` t2
on t1.first_name = t2.first_name
and t1.last_name = t2.last_name


as you can see, this would appear to be looking for people, however, in some cases, I have businesses in the tables. In those cases, first_name is used, and last_name is null.



this means I have a null = null scenerio, and fails join.



How do I tell bigquery to allow null = null, without having to put coalesce statements all over the place?



Thanks










share|improve this question



























    0















    I have a bigquery select statement where in some cases, the where clauses show null = null



    In the case of this statement:



    select * from `db.ds.table1` t1
    join `db.ds.table2` t2
    on t1.first_name = t2.first_name
    and t1.last_name = t2.last_name


    as you can see, this would appear to be looking for people, however, in some cases, I have businesses in the tables. In those cases, first_name is used, and last_name is null.



    this means I have a null = null scenerio, and fails join.



    How do I tell bigquery to allow null = null, without having to put coalesce statements all over the place?



    Thanks










    share|improve this question

























      0












      0








      0








      I have a bigquery select statement where in some cases, the where clauses show null = null



      In the case of this statement:



      select * from `db.ds.table1` t1
      join `db.ds.table2` t2
      on t1.first_name = t2.first_name
      and t1.last_name = t2.last_name


      as you can see, this would appear to be looking for people, however, in some cases, I have businesses in the tables. In those cases, first_name is used, and last_name is null.



      this means I have a null = null scenerio, and fails join.



      How do I tell bigquery to allow null = null, without having to put coalesce statements all over the place?



      Thanks










      share|improve this question














      I have a bigquery select statement where in some cases, the where clauses show null = null



      In the case of this statement:



      select * from `db.ds.table1` t1
      join `db.ds.table2` t2
      on t1.first_name = t2.first_name
      and t1.last_name = t2.last_name


      as you can see, this would appear to be looking for people, however, in some cases, I have businesses in the tables. In those cases, first_name is used, and last_name is null.



      this means I have a null = null scenerio, and fails join.



      How do I tell bigquery to allow null = null, without having to put coalesce statements all over the place?



      Thanks







      sql google-bigquery






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked Nov 25 '18 at 4:04









      arcee123arcee123

      75611536




      75611536
























          2 Answers
          2






          active

          oldest

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          2














          #standardSQL
          select * from `db.ds.table1` t1
          join `db.ds.table2` t2
          on t1.first_name = t2.first_name
          and ifnull(t1.last_name, '') = ifnull(t2.last_name, '')


          obviously ifnull is equivalent of coalesce so not sure if this is what you can accept as you mention you wanted not to use coalesce for some reason






          share|improve this answer


























          • This might be OK, but in the (possibly rare) case that empty string should be recorded as either last_name, this query could give false results.

            – Tim Biegeleisen
            Nov 25 '18 at 13:36






          • 1





            hope OP will be able to come with the appropriate value if '' will conflict with possible existing values for last name - if such edge cases exist

            – Mikhail Berlyant
            Nov 25 '18 at 15:18











          • well, I didn't want to have to put that on every field, but I guess there's no way around that.

            – arcee123
            Nov 29 '18 at 3:12











          • Just to clarify - Do you mean in your real use case you have multiple such fields like last name?

            – Mikhail Berlyant
            Nov 29 '18 at 3:58



















          3














          Make the last name optional, and allow both last names being NULL as valid:



          SELECT *
          FROM `db.ds.table1` t1
          INNER JOIN `db.ds.table2` t2
          ON t1.first_name = t2.first_name AND
          (t1.last_name = t2.last_name OR (t1.last_name IS NULL AND t2.last_name IS NULL));


          We could also try to write a query using COALESCE, but it isn't really clear what value should be used in place of a NULL last name.






          share|improve this answer























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            2 Answers
            2






            active

            oldest

            votes








            2 Answers
            2






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            2














            #standardSQL
            select * from `db.ds.table1` t1
            join `db.ds.table2` t2
            on t1.first_name = t2.first_name
            and ifnull(t1.last_name, '') = ifnull(t2.last_name, '')


            obviously ifnull is equivalent of coalesce so not sure if this is what you can accept as you mention you wanted not to use coalesce for some reason






            share|improve this answer


























            • This might be OK, but in the (possibly rare) case that empty string should be recorded as either last_name, this query could give false results.

              – Tim Biegeleisen
              Nov 25 '18 at 13:36






            • 1





              hope OP will be able to come with the appropriate value if '' will conflict with possible existing values for last name - if such edge cases exist

              – Mikhail Berlyant
              Nov 25 '18 at 15:18











            • well, I didn't want to have to put that on every field, but I guess there's no way around that.

              – arcee123
              Nov 29 '18 at 3:12











            • Just to clarify - Do you mean in your real use case you have multiple such fields like last name?

              – Mikhail Berlyant
              Nov 29 '18 at 3:58
















            2














            #standardSQL
            select * from `db.ds.table1` t1
            join `db.ds.table2` t2
            on t1.first_name = t2.first_name
            and ifnull(t1.last_name, '') = ifnull(t2.last_name, '')


            obviously ifnull is equivalent of coalesce so not sure if this is what you can accept as you mention you wanted not to use coalesce for some reason






            share|improve this answer


























            • This might be OK, but in the (possibly rare) case that empty string should be recorded as either last_name, this query could give false results.

              – Tim Biegeleisen
              Nov 25 '18 at 13:36






            • 1





              hope OP will be able to come with the appropriate value if '' will conflict with possible existing values for last name - if such edge cases exist

              – Mikhail Berlyant
              Nov 25 '18 at 15:18











            • well, I didn't want to have to put that on every field, but I guess there's no way around that.

              – arcee123
              Nov 29 '18 at 3:12











            • Just to clarify - Do you mean in your real use case you have multiple such fields like last name?

              – Mikhail Berlyant
              Nov 29 '18 at 3:58














            2












            2








            2







            #standardSQL
            select * from `db.ds.table1` t1
            join `db.ds.table2` t2
            on t1.first_name = t2.first_name
            and ifnull(t1.last_name, '') = ifnull(t2.last_name, '')


            obviously ifnull is equivalent of coalesce so not sure if this is what you can accept as you mention you wanted not to use coalesce for some reason






            share|improve this answer















            #standardSQL
            select * from `db.ds.table1` t1
            join `db.ds.table2` t2
            on t1.first_name = t2.first_name
            and ifnull(t1.last_name, '') = ifnull(t2.last_name, '')


            obviously ifnull is equivalent of coalesce so not sure if this is what you can accept as you mention you wanted not to use coalesce for some reason







            share|improve this answer














            share|improve this answer



            share|improve this answer








            edited Nov 25 '18 at 4:45

























            answered Nov 25 '18 at 4:33









            Mikhail BerlyantMikhail Berlyant

            57.4k43571




            57.4k43571













            • This might be OK, but in the (possibly rare) case that empty string should be recorded as either last_name, this query could give false results.

              – Tim Biegeleisen
              Nov 25 '18 at 13:36






            • 1





              hope OP will be able to come with the appropriate value if '' will conflict with possible existing values for last name - if such edge cases exist

              – Mikhail Berlyant
              Nov 25 '18 at 15:18











            • well, I didn't want to have to put that on every field, but I guess there's no way around that.

              – arcee123
              Nov 29 '18 at 3:12











            • Just to clarify - Do you mean in your real use case you have multiple such fields like last name?

              – Mikhail Berlyant
              Nov 29 '18 at 3:58



















            • This might be OK, but in the (possibly rare) case that empty string should be recorded as either last_name, this query could give false results.

              – Tim Biegeleisen
              Nov 25 '18 at 13:36






            • 1





              hope OP will be able to come with the appropriate value if '' will conflict with possible existing values for last name - if such edge cases exist

              – Mikhail Berlyant
              Nov 25 '18 at 15:18











            • well, I didn't want to have to put that on every field, but I guess there's no way around that.

              – arcee123
              Nov 29 '18 at 3:12











            • Just to clarify - Do you mean in your real use case you have multiple such fields like last name?

              – Mikhail Berlyant
              Nov 29 '18 at 3:58

















            This might be OK, but in the (possibly rare) case that empty string should be recorded as either last_name, this query could give false results.

            – Tim Biegeleisen
            Nov 25 '18 at 13:36





            This might be OK, but in the (possibly rare) case that empty string should be recorded as either last_name, this query could give false results.

            – Tim Biegeleisen
            Nov 25 '18 at 13:36




            1




            1





            hope OP will be able to come with the appropriate value if '' will conflict with possible existing values for last name - if such edge cases exist

            – Mikhail Berlyant
            Nov 25 '18 at 15:18





            hope OP will be able to come with the appropriate value if '' will conflict with possible existing values for last name - if such edge cases exist

            – Mikhail Berlyant
            Nov 25 '18 at 15:18













            well, I didn't want to have to put that on every field, but I guess there's no way around that.

            – arcee123
            Nov 29 '18 at 3:12





            well, I didn't want to have to put that on every field, but I guess there's no way around that.

            – arcee123
            Nov 29 '18 at 3:12













            Just to clarify - Do you mean in your real use case you have multiple such fields like last name?

            – Mikhail Berlyant
            Nov 29 '18 at 3:58





            Just to clarify - Do you mean in your real use case you have multiple such fields like last name?

            – Mikhail Berlyant
            Nov 29 '18 at 3:58













            3














            Make the last name optional, and allow both last names being NULL as valid:



            SELECT *
            FROM `db.ds.table1` t1
            INNER JOIN `db.ds.table2` t2
            ON t1.first_name = t2.first_name AND
            (t1.last_name = t2.last_name OR (t1.last_name IS NULL AND t2.last_name IS NULL));


            We could also try to write a query using COALESCE, but it isn't really clear what value should be used in place of a NULL last name.






            share|improve this answer




























              3














              Make the last name optional, and allow both last names being NULL as valid:



              SELECT *
              FROM `db.ds.table1` t1
              INNER JOIN `db.ds.table2` t2
              ON t1.first_name = t2.first_name AND
              (t1.last_name = t2.last_name OR (t1.last_name IS NULL AND t2.last_name IS NULL));


              We could also try to write a query using COALESCE, but it isn't really clear what value should be used in place of a NULL last name.






              share|improve this answer


























                3












                3








                3







                Make the last name optional, and allow both last names being NULL as valid:



                SELECT *
                FROM `db.ds.table1` t1
                INNER JOIN `db.ds.table2` t2
                ON t1.first_name = t2.first_name AND
                (t1.last_name = t2.last_name OR (t1.last_name IS NULL AND t2.last_name IS NULL));


                We could also try to write a query using COALESCE, but it isn't really clear what value should be used in place of a NULL last name.






                share|improve this answer













                Make the last name optional, and allow both last names being NULL as valid:



                SELECT *
                FROM `db.ds.table1` t1
                INNER JOIN `db.ds.table2` t2
                ON t1.first_name = t2.first_name AND
                (t1.last_name = t2.last_name OR (t1.last_name IS NULL AND t2.last_name IS NULL));


                We could also try to write a query using COALESCE, but it isn't really clear what value should be used in place of a NULL last name.







                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Nov 25 '18 at 4:09









                Tim BiegeleisenTim Biegeleisen

                222k1389142




                222k1389142






























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