DQL Overview
Data Query Language (DQL) is used to query and retrieve data from a database. The main focus of DQL commands is to fetch data based on specific conditions and return the results to the user. DQL provides flexibility in how data is queried, sorted, filtered, and grouped.
Common DQL Commands
| Command | Description |
|---|---|
SELECT | Retrieves data from one or more tables. |
FROM | Specifies the table from which to retrieve data. |
WHERE | Filters the records based on specified conditions. |
GROUP BY | Groups records with identical values in specified columns. |
ORDER BY | Sorts the retrieved data in ascending or descending order. |
HAVING | Filters groups based on specified conditions, used with GROUP BY. |
Purpose of DQL
DQL is crucial for extracting meaningful information from the database. It allows you to run powerful queries to retrieve data in a structured and efficient manner.