Beginner

36. SQL Expressions

Learn how SQL expressions combine values, columns, operators, and functions to produce results.

📘 Lesson 36 of 728 ⏱ 8 min 🎯 Beginner

A SQL expression is a combination of values, column references, operators, functions, or other expressions that produces a result. Expressions can be used for calculations, comparisons, text manipulation, conditional logic, and many other operations inside SQL queries.

Expressions allow analysts to create calculated values instead of relying only on information already stored in database columns. This is essential for creating meaningful business metrics and analytical results.

If an Employees table contains a monthly Salary column, an expression such as Salary * 12 can calculate an estimated annual salary.

SQL 
SELECT
    EmployeeName,
    Salary,
    Salary * 12 AS AnnualSalary
FROM Employees;

SQL expressions are used for financial calculations, sales metrics, employee analysis, reporting, data transformation, and business-rule implementation.

  • Expressions produce calculated or evaluated results.
  • Expressions can contain column references.
  • Expressions can use operators.
  • Expressions can use functions.
  • Expressions are useful for calculated business metrics.
What is a SQL expression?

A SQL expression combines values, columns, operators, functions, or other expressions to produce a result.

Give an example of a SQL expression.

Salary * 12 is an example of a SQL expression that calculates annual salary from monthly salary.

Have you finished this lesson?

Introduction to SQL – All Lessons