When Should I Use '= NULL' vs. 'IS NULL' in SQL?

Distinguishing " = null" from "IS NULL" in SQL Comparisons

The difference between " = null" and "IS NULL" in SQL lies in their usage in WHERE clauses and assignments.

WHERE Clause Usage

In a WHERE clause, using "column = null" is invalid. NULL represents an unknown or undefined value, and comparing it for equality is meaningless. Instead, use "column IS NULL" to check if a column is NULL or "column IS NOT NULL" to verify it is not NULL.

Assignment Usage

However, you can use " = null" to assign the NULL value to a column. For instance, the syntax "UPDATE TableX SET Column = NULL..." sets the specified column to NULL.

Additional Resources:

• Wikipedia: [NULL (SQL)](https://en.wikipedia.org/wiki/Null_(SQL))
• W3Schools: [SQL NULL Values](https://www.w3schools.com/sql/sql_null_values.asp)
• SQL Tutorial: [IS NULL Operator](https://www.tutorialspoint.com/sql/sql-is-null-operator.htm)

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