Query Optimizer Phases
The SQL Server Query Optimizer uses cost-based optimization to create an execution plan with the least cost.
Parent Table vs Child Table
Understanding the difference between Parent Tables and Child Tables and the difference between Primary Keys vs Foreign Keys.
Selecting From Mulitple Tables
How to write T-SQL SELECT statements using multiple tables and what are the differences between using Inner Joins, Left Outer Joins, Right Outer Joins, and Full Outer Joins.
Using the GROUP BY and HAVING Statements
In this post, we discuss how to use the GROUP BY and HAVING clause in a T-SQL statement.
SQL COALESCE Function
The SQL Coalesce function is used to when you want to combine values from a series of columns or expressions when they might contain NULL values.
NULL Values and Aggregate Functions
How to work with NULL values in Aggregate Functions in a T-SQL statement. How to fix issues with NULL vaules with the AVG() and COUNT() functions.
Using Aggregate Functions
How to use the COUNT, MAX, AVG, and SUM Aggregate Functions in a T-SQL statement.
What is a Function?
What is a SQL Function and how to use a function in a T-SQL statement? We use the GetDate() and LEFT() functions as examples.
Sort Records using ORDER BY
How to use the ORDER BY statement to sort records in a T-SQL statement in both ascending and descending order.
Filtering Records by NULL Values
How to use the WHERE statement to filter records when a value IS NULL or IS NOT NULL in a T-SQL statement.