MySQL DatabaseLesson 66Free preview

MySQL Where

This lesson is part of PHP · All levels

Summary

The WHERE clause filters the line so that only data that qualifies for a certain qualification will be included. Comparative operators such as =, >, <, LIKE, and BETWEEN are used to compile conditions, whereas NULL is checked with IS NULL. When the value comes from the user input, always wrap it up with a prepared statement.

Key points

WHERE is placed after FROM to limit the line taken.
Use IS NULL to check the empty value, not = NULL.
WHERE filters the line before the aggregation, while HAVING filters the result of GROUP BY.
The dynamic value of the user must pass through the binding parameter to be secure.

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