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Showing posts with the label Migrate Green plum distinct on to Redshift row_number()

Migrate Green plum distinct on to Redshift row_number()

Green plum distinct on To Redshift row_number: Green Plum: select distinct on (col_1, col_2, col_3) from table_t1 where condition_1=some_condition order by col_1, col_2, col_3 Rdshift: select col_1, col_2, col_3 as <alias> from      (      select row_number() over     (      partition by col_1 order by col_1      ) as rn, col_1, col_2, col_3      from table_1      where col_4=<condition>      order by col_1, col_2, col_3      ) as t1 where t1.rn=1 Note: If you include more columns for partition by clause, check the no. of row count, as it should be different.