Structured Query Language (SQL) is a powerful tool for managing and manipulating relational databases. When working with databases, it's common to encounter situations where you need to retrieve ...

This function returns the approximate number of unique non-null values in a group. :::image type="icon" source="../../includes/media/topic-link-icon.svg" border ...

Compares the equality of two expressions and guarantees a true or false result, even if one or both operands are NULL. Any valid expression. The expression can be a column, a constant, a function, a ...

Learn SQL basics in just 15 minutes with this tutorial focused on using SQL with MySQL. Topics covered include: - What SQL is and an overview of relational database management systems - Installing ...