---
title: "SQL query"
description: "A SQL query is a structured request written in Structured Query Language (SQL) that allows you to retrieve, analyze, or manipulate data stored in a database."
canonical: "https://motherduck.com/glossary/sql-query/"
related:
  - title: "DuckDB SQL | MotherDuck Docs"
    url: "https://motherduck.com/docs/sql-reference/duckdb-sql-reference/"
  - title: "Analyze JSON Data Using SQL and DuckDB"
    url: "https://motherduck.com/blog/analyze-json-data-using-sql/"
  - title: "query | MotherDuck Docs"
    url: "https://motherduck.com/docs/sql-reference/motherduck-cli/query/"
gated_asset:
  title: "DuckLake on MotherDuck"
  url: "https://motherduck.com/product/ducklake/"
---

# SQL query

> A SQL query is a structured request written in Structured Query Language (SQL) that allows you to retrieve, analyze, or manipulate data stored in a database.

## Definition
A SQL query is a structured request written in Structured Query Language (SQL) that allows you to retrieve, analyze, or manipulate data stored in a database. The most common type of query uses the `SELECT` statement to read data, though queries can also modify data using statements like `INSERT`, `UPDATE`, and `DELETE`.

<glossary-callout guide="duckdb-cheatsheet-full" />

## Basic Structure 
A typical SQL query starts with `SELECT` followed by the columns you want to retrieve, then `FROM` to specify the source table(s), and optionally `WHERE` to filter results. Additional clauses like `GROUP BY`, `HAVING`, and `ORDER BY` help shape and organize the output.

## DuckDB Examples
Here's a simple query that selects all columns from a table:

```sql
SELECT * FROM employees;
```

A more complex query showing filtering, grouping and ordering:

```sql
SELECT department, 
       COUNT(*) as employee_count,
       AVG(salary) as avg_salary
FROM employees
WHERE status = 'active'
GROUP BY department
HAVING COUNT(*) > 5
ORDER BY avg_salary DESC;
```

DuckDB extends standard SQL syntax by allowing you to omit the `SELECT` keyword when using `*`, making this valid:

```sql
FROM employees;
```

You can also use DuckDB's unique column selection syntax to dynamically select columns:

```sql
SELECT COLUMNS('salary_.*') 
FROM employees;
```

## Common Use Cases
Data analysts and engineers use SQL queries to perform tasks like generating reports, analyzing trends, cleaning data, and integrating different data sources. Queries can range from simple one-line statements to complex operations involving multiple joins, subqueries, and window functions.

## DuckDB-Specific Features
DuckDB optimizes queries for analytical workloads and supports querying data directly from files like CSV and Parquet without first loading them into tables. It also includes extensions to standard SQL that make common analytical tasks more convenient, such as simplified grouping syntax and enhanced column selection capabilities.