Oracle: select missing dates
I have a table with (among other things) dates in a field.
I need to get a list of all dates that are more recent than the oldest date, older than the most recent
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I'd opt for this variant, because it's more efficient:
with all_dates_wo_boundary_values as ( select oldest + level the_date from ( select min(the_date) oldest , max(the_date) recent from your_table ) connect by level <= recent - oldest - 1 ) select the_date from all_dates_wo_boundary_values minus select the_date from your_tableAnd here is some proof.
First the setup:SQL> create table your_table (the_date) 2 as 3 select date '2012-01-02' from dual union all 4 select date '2012-01-02' from dual union all 5 select date '2012-01-03' from dual union all 6 select date '2012-01-05' from dual union all 7 select date '2012-01-05' from dual union all 8 select date '2012-01-07' from dual union all 9 select date '2012-01-08' from dual 10 / Table created. SQL> exec dbms_stats.gather_table_stats(user,'your_table') PL/SQL procedure successfully completed. SQL> alter session set statistics_level = all 2 / Session altered.Horse's query:
SQL> with date_range as 2 ( select min(the_date) as oldest 3 , max(the_date) as recent 4 , max(the_date) - min(the_date) as total_days 5 from your_table 6 ) 7 , all_dates as 8 ( select ( select oldest from date_range) + level as a_date 9 from dual 10 connect by level <= (select total_days from date_range) 11 ) 12 select ad.a_date 13 from all_dates ad 14 left join your_table yt on ad.a_date = yt.the_date 15 where yt.the_date is null 16 order by ad.a_date 17 / A_DATE ------------------- 04-01-2012 00:00:00 06-01-2012 00:00:00 2 rows selected. SQL> select * from table(dbms_xplan.display_cursor(null,null,'allstats last')) 2 / PLAN_TABLE_OUTPUT -------------------------------------------------------------------------------------------------------------------------------------- SQL_ID gaqx49vb9gz9k, child number 0 ------------------------------------- with date_range as ( select min(the_date) as oldest , max(the_date) as recent , max(the_date) - min(the_date) as total_d ays from your_table ) , all_dates as ( select ( select oldest from date_range) + level as a_date from dual connect by level <= (select total_days from date_range) ) select ad.a_date from all_dates ad left join your_table yt on ad.a_date = yt.the_date where yt.the_date is null order by ad.a_date Plan hash value: 1419150012 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time | Buffers | Reads | Writes | OMem | 1Mem | Used-Mem | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | 1 | TEMP TABLE TRANSFORMATION | | 1 | | 2 |00:00:00.01 | 22 | 1 | 1 | | | | | 2 | LOAD AS SELECT | | 1 | | 1 |00:00:00.01 | 7 | 0 | 1 | 262K| 262K| 262K (0)| | 3 | SORT AGGREGATE | | 1 | 1 | 1 |00:00:00.01 | 3 | 0 | 0 | | | | | 4 | TABLE ACCESS FULL | YOUR_TABLE | 1 | 7 | 7 |00:00:00.01 | 3 | 0 | 0 | | | | | 5 | SORT ORDER BY | | 1 | 1 | 2 |00:00:00.01 | 12 | 1 | 0 | 2048 | 2048 | 2048 (0)| |* 6 | FILTER | | 1 | | 2 |00:00:00.01 | 12 | 1 | 0 | | | | |* 7 | HASH JOIN OUTER | | 1 | 1 | 7 |00:00:00.01 | 12 | 1 | 0 | 1048K| 1048K| 707K (0)| | 8 | VIEW | | 1 | 1 | 6 |00:00:00.01 | 9 | 1 | 0 | | | | | 9 | CONNECT BY WITHOUT FILTERING| | 1 | | 6 |00:00:00.01 | 3 | 0 | 0 | | | | | 10 | FAST DUAL | | 1 | 1 | 1 |00:00:00.01 | 0 | 0 | 0 | | | | | 11 | VIEW | | 1 | 1 | 1 |00:00:00.01 | 3 | 0 | 0 | | | | | 12 | TABLE ACCESS FULL | SYS_TEMP_0FD9D660C_81240964 | 1 | 1 | 1 |00:00:00.01 | 3 | 0 | 0 | | | | | 13 | TABLE ACCESS FULL | YOUR_TABLE | 1 | 7 | 7 |00:00:00.01 | 3 | 0 | 0 | | | | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------ Predicate Information (identified by operation id): --------------------------------------------------- 6 - filter("YT"."THE_DATE" IS NULL) 7 - access("YT"."THE_DATE"=INTERNAL_FUNCTION("AD"."A_DATE")) 32 rows selected.And my suggestion:
SQL> with all_dates_wo_boundary_values as 2 ( select oldest + level the_date 3 from ( select min(the_date) oldest 4 , max(the_date) recent 5 from your_table 6 ) 7 connect by level <= recent - oldest - 1 8 ) 9 select the_date 10 from all_dates_wo_boundary_values 11 minus 12 select the_date 13 from your_table 14 / THE_DATE ------------------- 04-01-2012 00:00:00 06-01-2012 00:00:00 2 rows selected. SQL> select * from table(dbms_xplan.display_cursor(null,null,'allstats last')) 2 / PLAN_TABLE_OUTPUT -------------------------------------------------------------------------------------------------------------------------------------- SQL_ID 7aavxmzkj7zq7, child number 0 ------------------------------------- with all_dates_wo_boundary_values as ( select oldest + level the_date from ( select min(the_date) oldest , max(the_date) recent from your_table ) connect by level <= recent - oldest - 1 ) select the_date from all_dates_wo_boundary_values minus select the_date from your_table Plan hash value: 2293301832 ----------------------------------------------------------------------------------------------------------------------------------- | Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time | Buffers | OMem | 1Mem | Used-Mem | ----------------------------------------------------------------------------------------------------------------------------------- | 1 | MINUS | | 1 | | 2 |00:00:00.01 | 6 | | | | | 2 | SORT UNIQUE | | 1 | 1 | 5 |00:00:00.01 | 3 | 9216 | 9216 | 8192 (0)| | 3 | VIEW | | 1 | 1 | 5 |00:00:00.01 | 3 | | | | | 4 | CONNECT BY WITHOUT FILTERING| | 1 | | 5 |00:00:00.01 | 3 | | | | | 5 | VIEW | | 1 | 1 | 1 |00:00:00.01 | 3 | | | | | 6 | SORT AGGREGATE | | 1 | 1 | 1 |00:00:00.01 | 3 | | | | | 7 | TABLE ACCESS FULL | YOUR_TABLE | 1 | 7 | 7 |00:00:00.01 | 3 | | | | | 8 | SORT UNIQUE | | 1 | 7 | 5 |00:00:00.01 | 3 | 9216 | 9216 | 8192 (0)| | 9 | TABLE ACCESS FULL | YOUR_TABLE | 1 | 7 | 7 |00:00:00.01 | 3 | | | | ----------------------------------------------------------------------------------------------------------------------------------- 22 rows selected.Regards,
Rob.
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