#Sql minify how to#

Other users running queries: The more queries running concurrently on a database, the more the database must process at a given time and the slower everything will run.Query runtime is also dependent on some things that you can't really control related to the database itself: Aggregations: Combining multiple rows to produce a result requires more computation than simply retrieving those rows.There's an example of this in the subqueries lesson. Joins: If your query joins two tables in a way that substantially increases the row count of the result set, your query is likely to be slow.Table size: If your query hits one or more tables with millions of rows or more, it could affect performance.First, let's address some of the high-level things that will affect the number of calculations you need to make, and therefore your querys runtime: To do this, you'll need some understanding of how SQL actually makes calculations. The way to make a query run faster is to reduce the number of calculations that the software (and therefore hardware) must perform. The theory behind query run timeĪ database is a piece of software that runs on a computer, and is subject to the same limitations as all software-it can only process as much information as its hardware is capable of handling.

#Sql minify how to#

In this lesson, you'll learn to identify when your queries can be improved, and how to improve them. The lesson on subqueries introduced the idea that you can sometimes create the same desired result set with a faster-running query. It's general purpose is to reduce the amount of time it takes a user to receive a result after issuing a query, and to reduce the amount of resources used to process a query. SQL tuning is the process of improving SQL queries to accelerate your servers performance.

Starting here? This lesson is part of a full-length tutorial in using SQL for Data Analysis.