SQL TutorialLesson 5Free preview

SQL Where

This lesson is part of SQL · All levels

Summary

The WHERE clause is used to filter the line so that only those who qualify for a particular qualification are included in the query. The condition can be a comparison of =, <>, >, >=, <, or <=. Without WHERE, the query will process all the rows in the table.

Key points

WHERE is placed after FROM and before ORDER BY.
Conditions support the comparison operator: =, <>, >, >=, <, <=.
The text value is written with a single quotation mark, while the numbers do not need to be quoted.
Logical operators AND, OR, and NOT can combine several conditions.
WHERE cannot use the aggregate function; for that use HAVING.

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