WebMar 11, 2024 · SQL Depends on Nothing This aggregate function returns the value from the first or last input row in each group, ignoring NULL rows. (NULLs are ignored automatically by the STRICT declaration, documented here ) The result depends on the sort order of input rows, which is arbitrary for unsorted input. WebThe IS NULL operator returns a boolean value of 1 if the value of column1 is null, and 0 otherwise. By sorting first on column1 IS NULL, we are making sure that all NULL values come last in the result set. Then, we sort on column1 ASC to sort the non-null values in ascending order. You can replace ASC with DESC to sort in descending order.
PostgreSQL: Documentation: 15: 9.21. Aggregate Functions
WebSep 9, 2024 · For PostgreSQL you could quite intuitively use: Photo.order ('collection_id DESC NULLS LAST') # NULLs come last MySQL specific For MySQL, you could put the minus sign upfront, yet this feature seems to be undocumented. Appears to work not only with numerical values, but with dates as well. Photo.order ('-collection_id DESC') # NULLs … WebNov 2, 2024 · 1 You can use a subquery: select t1.ts, case when a is null then (select a from tab t2 where t2.ts < t1.ts and a is not null order by a desc limit 1) else a end as a from tab t1; ts a -: -: 1 1 2 2 3 2 4 2 5 3 db<>fiddle here Share Improve this answer Follow answered Nov 2, 2024 at 10:35 McNets 23.2k 9 46 84 Add a comment the pedagogs.com
How ORDER BY and NULL Work Together in SQL LearnSQL.com
WebNulls last: It will sort all null values after non-nulls in PostgreSQL order by clause result set. This is an optional clause. How ORDER BY Function works in PostgreSQL? Normally without using order by function in PostgreSQL, data retrieve in an unspecified order. Using order by function in PostgreSQL, our data comes in the specified order. WebIn Informix, when you sort columns in ORDER BY clause NULL values go first for ascending order, and last for descending order.. In PostgreSQL, the default behavior is different, … WebCREATE INDEX test2_info_nulls_low ON test2 (info NULLS FIRST); CREATE INDEX test3_desc_index ON test3 (id DESC NULLS LAST); An index stored in ascending order with nulls first can satisfy either ORDER BY x ASC NULLS FIRST or ORDER BY x DESC NULLS LAST depending on which direction it is scanned in. siamchem