SQL Operators

Database administrators and users utilize SQL queries to manipulate and access the data of database tables and views. They employ reserved words and characters to perform arithmetic operations, logical operations, comparison operations, compound operations, etc.

What is SQL Operator?

An SQL operator is a reserved word or a character used primarily in an SQL statement’s WHERE clause to operate (s), such as comparisons and arithmetic operations. These Operators are used to specify conditions in an SQL statement and to serve as conjunctions for multiple conditions in a statement.

Furthermore, an SQL operator can be either a unary or binary operator. A unary operator (for example, unary + or unary – ) uses only one operand to perform the unary operation, whereas the binary operator (for example, + or – etc) uses two operands to perform the binary operation.

Types of SQL Operators

• Arithmetic operator
• Comparison operator
• Logical operator

Arithmetic Operators

We can use various arithmetic operators on the data stored in the tables. Arithmetic Operators are:

Operator	Description
+	The addition is used to perform an addition operation on the data values.
–	This operator is used for the subtraction of the data values.
/	This operator works with the ‘ALL’ keyword and it calculates division operations.
*	This operator is used for multiplying data values.
%	Modulus is used to get the remainder when data is divided by another.

Comparison Operators

Another important operator in SQL is a Comparison operator, which is used to compare one expression’s value to other expressions. SQL supports different types of comparison operators, which is described below:

Operator	Description
=	Equal to.
>	Greater than.
<	Less than.
>=	Greater than equal to.
<=	Less than equal to.
<>	Not equal to.

Logical Operators

The Logical operators are those that are true or false. They return true or false values to combine one or more true or false values.

Operator	Description
AND	Logical AND compares two Booleans as expressions and returns true when both expressions are true.
OR	Logical OR compares two Booleans as expressions and returns true when one of the expressions is true.
NOT	Not takes a single Boolean as an argument and change its value from false to true or from true to false.

Special Operators

Operators	Description
ALL	ALL is used to select all records of a SELECT STATEMENT. It compares a value to every value in a list of results from a query. The ALL must be preceded by the comparison operators and evaluated to TRUE if the query returns no rows.
ANY	ANY compares a value to each value in a list of results from a query and evaluates to true if the result of an inner query contains at least one row.
BETWEEN	The SQL BETWEEN operator tests an expression against a range. The range consists of a beginning, followed by an AND keyword and an end expression.
IN	The IN operator checks a value within a set of values separated by commas and retrieves the rows from the table that match.
EXISTS	The EXISTS checks the existence of a result of a subquery. The EXISTS subquery tests whether a subquery fetches at least one row. When no data is returned then this operator returns ‘FALSE’.
SOME	SOME operator evaluates the condition between the outer and inner tables and evaluates to true if the final result returns any one row. If not, then it evaluates to false.
UNIQUE	The UNIQUE operator searches every unique row of a specified table.

Conclusion

SQL operators are fundamental tools for constructing precise and efficient queries, allowing users to specify conditions, perform calculations, and manipulate data according to their requirements. Understanding and effectively utilizing these operators are crucial skills for both database administrators and users working with SQL databases.

Frequently Asked Questions