A comparison operator is a reserved word used in an SQL statement WHERE clause to compare the two elements. These operators are used to enumerate conditions in an SQL statement, and to serve as conjunctions for multiple conditions in a statement. One such operator is SQL Not Equal, which we will discuss in this article.
In this article, we will look into the following topics.
- SQL Not Equal Operator
- The Return value of SQL Not Equal
- Example 1
- Example 2
- Example 3
- Example 4
SQL Not Equal Operator: !=
When both SQL expressions are not equal, this operator returns 1 and when they are equal, it returns 0, and when either expression is NULL, it returns NULL. When the expressions return different types of data, (for example, a string and a number), type conversion is performed.
The SQL Not Equal comparison operator (!=) is used to compare two expressions. For example, 15 != 17 comparison operation uses SQL Not Equal operator (!=) between two expressions 15 and 17.
Note: “!=” and “<>” both will give the same results.
SELECT * FROM customers WHERE name <> ‘Joe’
SELECT * FROM customers WHERE name != ‘Joe’
The above query will produce all the results where the name is not equal to Joe.
Both the query will produce the same result.
The Return Value Of SQL Not Equal
SQL Not Equal is a boolean expression. It can return either True (if one expression is not equal to another) or False (if the expressions are equal).
1 != 2 -----> True
3 != 3 -----> False
Example 1: Get all customer details except customer_id 1
The above-given code will exclude the details of customer_id 1.
Example 2: Get a list of all customers except one specific customer
The above example will exclude the details of the customer whose first name is Elka.
Example 3: Specifying multiple conditions using SQL Not Operator
We can specify multiple conditions for Not operator using the WHERE clause.
The statement given above will produce the following results.
Example 4: SQL Not operator and SQL Group By clause
SQL Not operator can also be used with the combination of GROUP BY and HAVING clause in the following way:
The city whose sum of points is equal to 3220 is excluded from the results.
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Through this article, you have now gained a solid understanding of SQL Not equal Operator, along with pertinent examples. Equality operator improves the performance of the SQL query.
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