What is the difference between LATERAL JOIN and a subquery in PostgreSQL?
Since Postgres came out with the ability to do LATERAL joins, I’ve been reading up on it, since I currently do complex data … Read more
subquery
Is there a performance difference between CTE , Sub-Query, Temporary Table or Table Variable?
In this excellent SO question, differences between CTE and sub-queries were discussed. I would like to specifically ask: In what circumstance is each … Read more
Remove duplicate rows in MySQL
I have a table with the following fields: id (Unique) url (Unique) title company site_id Now, I need to remove rows having same … Read more
updating table rows in postgres using subquery
Using postgres 8.4, My goal is to update existing table: CREATE TABLE public.dummy ( address_id SERIAL, addr1 character(40), addr2 character(40), city character(25), state … Read more
What is the error “Every derived table must have its own alias” in MySQL?
I am running this query on MySQL SELECT ID FROM ( SELECT ID, msisdn FROM ( SELECT * FROM TT2 ) ); and … Read more
Nested select statement in SQL Server
Why doesn’t the following work? SELECT name FROM (SELECT name FROM agentinformation) I guess my understanding of SQL is wrong, because I would … Read more
MySQL Error 1093 – Can’t specify target table for update in FROM clause
I have a table story_category in my database with corrupt entries. The next query returns the corrupt entries: SELECT * FROM story_category WHERE … Read more
Join vs. sub-query
I am an old-school MySQL user and have always preferred JOIN over sub-query. But nowadays everyone uses sub-query, and I hate it; I … Read more