I have 2 tables in Postgres, one is of about 200M records, and the other a few hundreds. I want to get 10 values from the small table and find the corresponding values in the long table. both are indexed.…
I am very rusty on MYSQL and having trouble updating columns based on a different column in a different record. I'm thinking I need to do a subquery but would appreciate help in how to do this. The table being…
I have 3 tables: products, product_options and product_option_choices. Products can have multiple options, options can have multiple choices. Choices can adjust the main product price (choice_price_adjust field). What I'm trying to do is fetch the products and have a field…
Table tblStudents columns: id, name, gender, SchoolName, SchoolId. Table tblSchool columns: id, name, location. select name, (select name from tblStudents as a where a.SchoolId=id limit 1) from tblSchool; I am looking to return SchoolName along with the first student enrolled…
I select data from temporary table: CREATE TEMPORARY TABLE IF NOT EXISTS "tmp" ( "fuel_type" TEXT, "litres" NUMERIC(8,2), "is_rent" BOOLEAN ); insert into tmp values ('petrol', 10, False); insert into tmp values ('petrol', 20, False); insert into tmp values ('diesel',…
I have two SQL queries like this for postgresql: The first query is fetching subscriptions that were never synced or that were updated recently and synced a long time ago: SELECT * FROM subscriptions WHERE (last_sync_at IS NULL OR last_sync_at…
I have a table for recording the mark a student got in a subject on a particular date. The table, perf, has columns id,date,student,subject,mark. Objective: I want to compare the mark obtained by a student against the highest, the lowest…
I have a result set of parent categories and subcategories. I want to exclude all parent categories if a subcategory exists in the results. What I would do is using a NOT IN in the query, but that requires a…
I am using mysql workbench 8.0 I am teaching myself SQL and am currently starting on some guided projects with a LOT of googling. Right now I am working with this data: Here's the relevant section I am working with:…
I have searched on the forums and failed to find how can one name columns for a values statement subquery. Here is my query in MySQL: SELECT * FROM (VALUES ('PPA', 'blah', 30) , ('PPB', 'blah blah', 60) ) AS…