How to express inequality in sql

The syntax for expressing inequality in SQL is "!=". Its usage is: column name != value. Additionally, you can use "<>" instead of "!=", and for NULL values, use IS NULL or IS NOT NULL for comparison. In the WHERE clause, multiple not-equal conditions can be concatenated to form complex queries.

The syntax for expressing not equal in SQL

In SQL, use the "!=" operator to express not equal equal.

Usage:

<code class="sql">列名 != 值</code>

For example:

<code class="sql">SELECT * FROM table_name WHERE column_name != 'value';</code>

Other notes:

• You can use "<>" instead of "!=".
• For NULL values, use IS NULL or IS NOT NULL to compare.
• For numeric comparisons, you can also use the "<", ">", "<=", ">=" operators.
• When using "!=" in the WHERE clause, multiple conditions can be connected to form a complex query.

The above is the detailed content of How to express inequality in sql. For more information, please follow other related articles on the PHP Chinese website!