Why Use 'WHERE 1=1 AND ' in Dynamic SQL Queries and View Definitions?

Reasons for using WHERE 1=1 AND in SQL queries

When building SQL queries dynamically at runtime, determining whether one or zero conditions exist can be inconvenient. Use WHERE 1=1 AND to ensure that the query always has at least one condition.

Application in view definition

In the context of a view definition, the purpose is similar. When connecting conditions dynamically, the initial AND requires a condition to be appended. By starting with 1=1, subsequent conditions can be attached regardless of the number of existing conditions.

Example

Consider the following example:

<code class="language-sql">CREATE VIEW vTest AS
SELECT * FROM Table WHERE 1=1 AND table.Field=Value</code>

By starting with 1=1, even without other conditions, the construction of the view is simplified. If you have multiple conditions, you can use AND to append them.

Not a SQL injection protection measure

Contrary to popular belief, WHERE 1=1 AND does not prevent SQL injection. A condition injected of the form "1=1" OR still has the same result as the injection code alone.

Conclusion

In summary, using WHERE 1=1 AND is a simple way to build dynamic SQL queries or define views when the number of conditions is unknown. However, it should not be mistaken as a security measure against SQL injection.

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