Skip to content
Advertisement

Tag: left-join

Get one record per ID

I’m trying to retrieve data from 2 tables A&B. , there are multiple data rows in B for each PrimaryKey from A. But I want to get only the first record for every ID from tableA. How can I achieve this? Answer SQL tables represent unordered sets so there is no first row. But you can get an arbitrary row

Counting organizations which user has not contacted

I am new at PostgreSQL. I have the following tables created in my schema: User table: Organization table: And finally Organization_rating table: With this schema, an organization has a business type in which gives support to the user that also have that business type. After giving this support, the user can rate this organization with organization_rating. Following this logic, I

Conceptual explanation: why COUNT() syntax doesn’t work on SQLZoo JOIN Lesson Challenge 13?

I’ve got solutions here in stack overflow for SQLZoo Join Lesson Challenge 13 problem link: https://sqlzoo.net/wiki/The_JOIN_operation solution link: SQLzoo JOIN tutorial #13 But, before to use the solution that I found here, I was trying: But the answer is always wrong. I have a spreadsheet where I put the results Correct X Actual. link to the results I’ve got: https://docs.google.com/spreadsheets/d/1uTHfgbvuDBbPrVIaXX-i-RGny5uK1j6wJYwmTNUZ7sQ/edit#gid=0

Using left join to query and match JSON field in MySQL

Table A,field : pay_type_fk,type:json, Examples Data: [1,2,4] Table B,field : id type : bigint Examples Data: primary key SQL I use: Only pay can be found_ For the first record in the type table, I think we can query all of them with group_ CONCAT Answer If I follow you correctly, you can join on JSON_CONTAINS(): That said, a better

Advertisement