I'm reviewing a MySQL query and came across a keyword I've never seen before - "excludes". It's used in a DELETE statement similar to: DELETE table_A FROM table_A JOIN ( SELECT DISTINCT table_A.field FROM table_A JOIN table_B USING (field) LEFT…
I was wondering why this line that is underlined in red isnt AVG(tenure) OVER() AS avg_tenure? The output table is correct the way it is below, but not sure when we should use AVG() normally vs. AVG() OVER() as a…
I am trying to rewrite a Postgres schema to fit the MySQL (8.0.32) dialect. As you know, MySQL does not support partial indexes. In the following situation, there exists an index that enforces unique data on customer_group.name only when deleted_at…
I have a MySQL table with ~400 columns The columns are accumulated from external data so I don't really have control over the count initially at least In the interest of avoiding errors whilst making columns, these are just TEXT…
I have a compound index on 3 columns. Now I want to execute the query based on only 2 columns, which both are not indexed. So the query takes long time to execute. How to I make use of the…
I have two queries that I want to run against a certain type of product, to check whether a product exists with certain specifications. Therefore I first want to check if a product contains a type=A, and if so check…
Data: user_choices table id userid choices 1 3 1,2,3 2 55 5 3 783 2,6,7 4 45 1,4 5 5 1,2,3,4,5,6,7 How can I query this table to explode the choices column filtered only to show values 1 or 2…
If I do: SELECT a, a FROM myTable I can get back the "a" value two times, and that's fine, it works. But I want to do something like: SELECT DISTINCT(a) AS a1, DISTINCT(a) AS a2 FROM myTable Of course…
I've read the MySQL docs, and questions wasn't an answer to my question. visited question 1, visited question 2 - while connection polling and facing error , visited question 3 My question on db Exchange I've set MySQL's GLOBAL wait_timeout…
I have a problem in my program where if I try to update a table and replace the value of a foreign key column, which is not null, with the value null, that it doesnât update the table. Here is…