what is in operator in sql

1SELECT * FROM Customers
2WHERE Country NOT IN ('Germany', 'France', 'UK');

1=	Checks if the values of two operands are equal or not, if yes then condition becomes true.	(a = b) is not true.
2!=	Checks if the values of two operands are equal or not, if values are not equal then condition becomes true.	(a != b) is true.
3<>	Checks if the values of two operands are equal or not, if values are not equal then condition becomes true.	(a <> b) is true.
4>	Checks if the value of left operand is greater than the value of right operand, if yes then condition becomes true.	(a > b) is not true.
5<	Checks if the value of left operand is less than the value of right operand, if yes then condition becomes true.	(a < b) is true.
6>=	Checks if the value of left operand is greater than or equal to the value of right operand, if yes then condition becomes true.	(a >= b) is not true.
7<=	Checks if the value of left operand is less than or equal to the value of right operand, if yes then condition becomes true.	(a <= b) is true.
8!<	Checks if the value of left operand is not less than the value of right operand, if yes then condition becomes true.	(a !< b) is false.
9!>	Checks if the value of left operand is not greater than the value of right operand, if yes then condition becomes true.	(a !> b) is true.

1(IN) operator in sql like "OR" operator
2For example: 
3Select * From employees
4Where department_id "IN" (60,90); 
5

1IN condition allows you to easily test
2if an expression matches any value in a list of values.
3It is for reducing  multiple OR
4conditions in a SELECT, INSERT,
5UPDATE, or DELETE statement.

1SELECT EmpId FROM EmployeeDetails
2UNION 
3SELECT EmpId FROM EmployeeSalary;
4