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How to join multiple columns in PostgreSQL stack?
Which works fine for that column, but I have a very large number of columns to work through, so would prefer it if there was a way to do this within an SQL query. I now have the following query (many thanks to banazs):
How to do multiple counts in PostgreSQL 9.6?
I have a table (PostgreSQL 9.6) containing 2.6 million+ timestamped rows associated with account identifiers, and for any given identifier, I want to count the total number of occurrences as well as just the number of occurrences today in a single query.
How does SQL join + count per row work?
Summary: It joins the questions table to the attempts table, only considers rows where correct is true, groups by the question id, sorts by the count of true attempts per question, and then limits to the top five results. I haven’t tested it, but I think it should at least be close to what you are looking for.
How to do a PostgreSQL subquery in SELECT clause?
How to do a Postgresql subquery in select clause with join in from clause like SQL Server? select name, author_id, count (1), (select count (1) from names as n2 where n2.id = n1.id and t2.author_id = t1.author_id ) from names as n1 group by name, author_id This would certainly work on Microsoft SQL Server but it does not at all on postegresql.
How to select columns by column in PostgreSQL?
I have a simple table with a unit_id oid, time timestamp, diag bytea. The primary key is a combination of both time and unit_id. The idea behind this query is to get the latest row (largest timestamp) for each unique unit_id. However the rows for each unit_id with the latest time are not always returned.
How to select all columns but group by one column?
The primary key is a combination of both time and unit_id. The idea behind this query is to get the latest row (largest timestamp) for each unique unit_id. However the rows for each unit_id with the latest time are not always returned. I really want to group by just the unit_id, but postgres makes me use diag also, since I am selecting that.
How to query Act codes in PostgreSQL stack?
The act_codes table is basically a table of activities (with a code and a description), and the data table contains the activity codes for (in this case) 4 different times (act1_1, act1_2, act1_3 and act1_4). I am trying to query this to get a table of counts for each activity.