# Introduction to T-SQL

T-SQL is the language SQL Server speaks. You will ask your first questions of a database with SELECT, choose and calculate columns, sort and limit results, and filter rows with WHERE.

Updated: November 3, 2026

## [SELECT in T-SQL](https://www.ask-codey.com/courses/csharp-full-stack-bootcamp/topics/select-in-t-sql)

1. [SELECT in T-SQL: an overview](https://www.ask-codey.com/lessons/select-in-t-sql-an-overview) (Novice): A SELECT statement asks the database a question and gets back a table of answers; T-SQL is SQL Server's version of SQL.
2. [SELECT Query Structure](https://www.ask-codey.com/lessons/select-in-t-sql-select-query-structure) (Novice): A SELECT statement is built from clauses that always appear in the same order; this chapter uses SELECT, FROM, WHERE and ORDER BY.
3. [Simple SELECT Query](https://www.ask-codey.com/lessons/select-in-t-sql-simple-select-query) (Novice): SELECT \* FROM a table returns every column and every row, the quickest way to see what a table holds.
4. [Specifying Columns](https://www.ask-codey.com/lessons/select-in-t-sql-specifying-columns) (Novice): List the columns you want, in the order you want them, and rename them in the result with AS.
5. [Calculations in Columns](https://www.ask-codey.com/lessons/select-in-t-sql-calculations-in-columns) (Apprentice): Work out new values as you query, with arithmetic on a row's columns and joined text, and give each calculated column a name.
6. [TOP and ORDER BY](https://www.ask-codey.com/lessons/select-in-t-sql-top-and-order-by) (Novice): Sort a query's results with ORDER BY, ascending or descending, by one column or several, and keep only the first rows with TOP.

## [WHERE in T-SQL](https://www.ask-codey.com/courses/csharp-full-stack-bootcamp/topics/where-in-t-sql)

1. [WHERE in T-SQL: an overview](https://www.ask-codey.com/lessons/where-in-t-sql-an-overview) (Novice): A WHERE clause keeps only the rows that match a condition, such as the customers in one country.
2. [Types of Filters](https://www.ask-codey.com/lessons/where-in-t-sql-types-of-filters) (Apprentice): Filter numbers and dates with comparison operators, text with LIKE patterns, lists with IN, ranges with BETWEEN, and missing values with IS NULL.
3. [Using Multiple Condition Filters](https://www.ask-codey.com/lessons/where-in-t-sql-using-multiple-condition-filters) (Apprentice): Combine conditions in a WHERE clause with AND, OR and NOT, and use parentheses so they're checked the way you mean.

Source: https://www.ask-codey.com/courses/csharp-full-stack-bootcamp/chapters/introduction-to-t-sql