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Using Criteria in SQL Queries

Written by Andrew Gould

In this tutorial

The WHERE Clause
The Structure of Basic Criteria
Should You Use Brackets to Contain Criteria?
What's Next?

This tutorial teaches you how to add criteria to your SQL queries to find specific records in a table. You'll learn about how to work with text, dates and numbers in the WHERE clause of a query.

The WHERE Clause

If you've read our tutorial on basic SQL queries you'll remember that the WHERE clause is the third of six keywords in a basic query. If you didn't read that tutorial or you just need a reminder here's where it fits in:

SELECT

FROM

WHERE

GROUP BY

HAVING

ORDER BY

The Structure of Basic Criteria

The most basic criteria you can write in SQL queries involve comparing the value of a field against another value that you provide. In the example below we're comparing the value of the FilmRunTimeMinutes field with the value 120 and asking if they are equal to each other:

SELECT

FilmName

,FilmRunTimeMinutes

FROM

tblFilm

WHERE

FilmRunTimeMinutes = 120

When this query is executed we'll return all of the films whose running time is equal to the number we have provided:

These films all last for 120 minutes.

Should You Use Brackets to Contain Criteria?

You might sometimes see people writing their criteria contained within parentheses, as shown below:

SELECT

FilmName

,FilmRunTimeMinutes

FROM

tblFilm

WHERE

(FilmRunTimeMinutes = 120)

With such a simple query the brackets make no difference to the results and so you can happily leave them out.

For more complex combinations of criteria you may find brackets helpful to clarify your query for other readers. A later part of this blog series shows an example where using brackets is essential for SQL Server to understand what you're trying to do!

What's Next?

Now that you know the basics of where the WHERE clause fits and what it's for, it's time to look in more detail at criteria involving specific data types; starting with numbers.

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tutorial

Writing queries

Previous
part

Top of page

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part

Criteria Using Numbers

Next
tutorial

WHERE criteria (version B)

You can learn more about this topic on the following Wise Owl courses:

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Online tutorials

Tutorials on SQL

WHERE criteria (version A)

Using Criteria in SQL Queries

The WHERE Clause

The Structure of Basic Criteria

Should You Use Brackets to Contain Criteria?

What's Next?

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