Explain what is a merge join in the SQL Server engine, test ordered inputs and duplicates, and compare merge, hash, and nested loops plans.
SQL SERVER – Why Should You Not to Use Old Style JOIN?
You can join tables with ANSI INNER JOIN or the old style JOIN in the WHERE clause. Here is an example that shows why you should avoid the old style JOIN.
Interview Question of the Week #038 – What is Left Semi Join Showplan Operator?
Understand the left semi join showplan operator with EXISTS, compare anti and inner joins, and inspect graphical-plan properties.
SQL SERVER – What is the Difference Between An INNER JOIN and WHERE Clause
What is the difference between an INNER JOIN and WHERE clause join? Very little in results or speed, but I explain why I still prefer INNER JOIN.
Comparing Two Schemas With sys.columns and a FULL OUTER JOIN
Use read-only queries for comparing two schemas, finding missing columns, checking type details, and reviewing indexes and modules.
SQL SERVER – Does Use of CTE Change the Order of Join in Inner Join
A reader said he uses a CTE to control join order. Does a CTE change the order of join in an inner join? Here is what I found.
MySQL – How to do Natural Join in MySQL? – A Key Difference Between Inner Join and Natural Join
MySQL supports NATURAL JOIN, which maps matching columns from both tables on its own. I show how it works and the key difference from INNER JOIN.