SQL <>

How do you compare values to ensure they are not equal in SQL?

The `<>` operator in SQL is used to check if two values are not equal. It's a crucial part of filtering data and creating complex queries. This operator is often used in `WHERE` clauses to select rows that don't match a specific condition.

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Description

Example H2

Example H3

The `<>` operator, also sometimes represented as `!=`, is a fundamental comparison operator in SQL. It's used to determine if two values are different. This operator is essential for filtering data based on conditions where equality is not the desired outcome. For instance, you might want to find all customers who haven't placed an order in the last month. The `<>` operator allows you to specify this condition precisely. It's a crucial part of the `WHERE` clause, which is used to filter rows in a result set. The `<>` operator is particularly useful in conjunction with other comparison operators and logical operators to create more complex filtering criteria. For example, you could combine `<>` with `AND` or `OR` to select rows that meet multiple conditions.

Why SQL <> is important

The `<>` operator is vital for data filtering and manipulation. It allows you to isolate specific data points that don't meet a particular criterion, which is essential for tasks like reporting, analysis, and data manipulation. Without this operator, you'd be limited in your ability to create complex queries that target specific subsets of data.

SQL <> Example Usage


CREATE TABLE Customers (
    CustomerID INT PRIMARY KEY,
    FirstName VARCHAR(50),
    LastName VARCHAR(50),
    Email VARCHAR(100),
    City VARCHAR(50)
);

CREATE TABLE Orders (
    OrderID INT PRIMARY KEY,
    CustomerID INT,
    OrderDate DATE,
    TotalAmount DECIMAL(10, 2),
    FOREIGN KEY (CustomerID) REFERENCES Customers(CustomerID)
);

SQL <> Syntax

Common Mistakes

Forgetting to use the `<>` operator when comparing values.
Using the incorrect operator (e.g., `=` instead of `<>` or vice versa).
Misunderstanding the difference between `<>` and other comparison operators (e.g., `>` or `<`).
Using `<>` with data types that don't support comparison (e.g., `NULL` values).

Frequently Asked Questions (FAQs)

When should I use the <> (or !=) operator instead of = in SQL?

Use the <> operator whenever you need to return rows where two values are different. For example, to identify customers who have not placed an order in the last month, you could compare the order date to the current date and filter with <>. Unlike =, which matches exact equality, <> is designed specifically for inequality checks and is recognized by all major SQL dialects.

Can I combine the <> operator with AND or OR for more complex filtering?

Absolutely. The <> operator works seamlessly with logical operators like AND and OR, allowing you to build multi-condition filters. For instance: WHERE status <> 'inactive' AND last_purchase < DATE_SUB(CURDATE(), INTERVAL 30 DAY) filters active customers whose last purchase was over 30 days ago. Chaining conditions in this way helps you create precise, business-focused queries.

How does Galaxy help me write and manage queries that use the <> operator?

Galaxy’s modern SQL editor offers smart autocompletion, AI-powered suggestions, and inline validation, so you can insert the <> operator correctly without syntax errors. The AI copilot can even refactor existing = conditions into <> comparisons when your requirements change. Once your query is ready, you can save it to a Collection, share it with teammates, and get it officially endorsed—eliminating copy-pasting SQL in Slack or Notion.