However, the symbol is not recognized as a valid operator in some versions of SQL, so it's important to use the != symbol instead. This is a common source of confusion for beginners, who may mistakenly use the symbol instead. Note that the NOT EQUAL operator is represented by the != symbol in SQL. This query will return all employees who have a salary that is not equal to $50,000, including those with salaries less than and greater than $50,000. However, if you want to exclude these employees and only see those who do not have a salary greater than $50,000, you can use the NOT EQUAL operator, like this: SELECT * FROM employees WHERE salary != 50000 This query will return all employees who have a salary greater than $50,000. You can use the NOT EQUAL operator with the greater than operator (>), like this: SELECT * FROM employees WHERE salary > 50000 These operators allow you to define specific criteria for the data that you want to include or exclude from your query results.įor example, suppose you have a table of employees and you want to find all employees who do not have a salary greater than $50,000. When filtering data with SQL, the NOT EQUAL operator can be used in combination with other comparison operators such as =,, =.
Using SQL NOT EQUAL With Multiple Criteria. Using SQL NOT EQUAL With Basic Operators. The NOT EQUAL operator allows you to filter out data that does not match a particular value or set of values. SQL provides a variety of operators for filtering data, including the NOT EQUAL operator (!=). One of the most common tasks when working with databases is filtering data based on specific criteria. It’s a good practice to map intention with action so that, if something goes wrong, you can check either the initial information or the expression itself.Structured Query Language (SQL) is a powerful tool for managing and analyzing data. Do this before you do the expression so that you think before you do. If you can, regardless of where you use the expressions, try to add a comment indicating what you are trying to do. If something comes from the source that you don’t expect, you’ll have a hard time knowing what conditions are the correct ones, so keep things simple to debug things easily. Keeping expressions as small as possible is a good practice. You can combine multiple equal operators but keep them to a minimum. Use it with care since if you forget to filter the data in your code, you can display data that should not be there. You can have a column for soft-deletion called “Is Deleted.” Having the data that is “not deleted” is quite useful and makes data recovery easier. It’s ideal for hiding data.Īnother amazing usage for it is to hide data that you don’t want to see. This is only possible with a “not equals” operator since you’re looking for something that should not be there. For example, a column with a pre-defined list of values and has a value that is not on that list should be flagged. You can create expressions that find cases where it returns something we need to clean the data. I’ve mentioned above, but the “not equals” operator is ideal to find edge cases or information that is not correct. Use it when it makes “sense.”ĭepending on how your columns are named, you may want to use the “not equals” operator instead of the “equals.” For example, if a column is named “Is Consultant” and you want to get the employees, you can use the “equals” to false, but it makes more sense to read it as “is a consultant not equals to true.” The result is the same, but how the expression is written makes it much clear its intention. Be careful with this since more exceptions may come that are not considered in your expression and result in invalid data. Often the “not equals” operator is used to remove exceptions. It’s a lot more work to filter the data that we don’t want than to filter only the data we want. 
Prefer the equals operator to get the data that you want. Querying for something that “isn’t” something is a shift of mindset, so use it only when it makes sense. People tend to think in a “positive” way. If possible, prefer the “equals” operator.
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