The SQL COALESCE function is a conditional expression that returns the first non-null value from a list of arguments. It can take any number of arguments, as long as they are compatible data types.

Avoid using any function on the column in the WHERE clause to replace and compare null values. for example WHERE ISNULL (col1,0)=0. Using row compression consolidate the NULLs, less IOs, hence ...

This repository contains SQL queries from various popular online learning resources e.g. Vertabelo Academy, SQLZoo etc. - ybg345/sql-hands-on ...