SQL operators are special symbols or keywords that are used to perform various operations on data stored in a database. These operators are used to retrieve, modify, and manipulate data in a database. In this response, I will describe some of the most common SQL operators.
Arithmetic operators:
Arithmetic operators are used to perform mathematical operations on numeric data in the database. The four basic arithmetic operators are:
Addition (+)
Subtraction (-)
Multiplication (*)
Division (/)
Comparison operators:
Comparison operators are used to compare values in the database. These operators return a Boolean value (true or false) based on the comparison result. The comparison operators in SQL include = (equal to), <> or != (not equal to), < (less than), > (greater than), <= (less than or equal to), and >= (greater than or equal to).
Logical operators:
Logical operators are used to combine two or more conditions to form a more complex condition. The three logical operators are:
AND: returns true if all conditions are true.
OR: returns true if any condition is true.
NOT: returns the opposite of the condition (true becomes false and vice versa).
String operators:
String operators are used to manipulate text or string data in the database. Some common string operators are:
CONCAT operator: used to combine two or more strings into one.
LIKE operator: used to match patterns in strings.
SUBSTRING operator: used to extract a substring from a string.
Set operators:
Set operators are used to combine or compare two or more sets of data. The most common set operators are:
UNION: used to combine two or more tables or result sets into a single table or result set.
UNION ALL operator: used to combine the results of two or more SELECT statements into a single result set. Unlike the UNION operator, which removes duplicate rows from the result set, the UNION ALL operator retains all rows from all SELECT statements.
INTERSECT: used to retrieve only the rows that are common to two or more tables or result sets.
EXCEPT: used to retrieve only the rows that are unique to one table or result set.
Other operators:
ALL operator is used to compare a value with all the values returned by a subquery.
ANY operator is used to compare a value with any of the values returned by a subquery.
BETWEEN operator is used to select values within a range. It can be used in a WHERE clause to retrieve data that falls within a specified range of values.
IN operator is used to specify multiple values in a WHERE clause. It allows you to retrieve data that matches any of the values in a specified list.
EXISTS operator is used to check whether a subquery returns any rows. It can be used in a WHERE clause to filter the results based on the existence of rows in another table.
NOT EXISTS operator is used to check if a subquery returns any rows. If the subquery returns no rows, then the NOT EXISTS operator returns true.
These are just a few of the many SQL operators available for working with databases. By understanding these operators, you can effectively manipulate and analyze data in a database.