SQL

sql and

/* AND is a operator that allows you to combine two conditions
Both conditions must be true for the row to b e included in the result set */
SELECT column_name(s)
FROM table_name
WHERE column_1 = value_1
AND column_2 = value_2;

operator in sql

=	Checks if the values of two operands are equal or not, if yes then condition becomes true.	(a = b) is not true.
!=	Checks if the values of two operands are equal or not, if values are not equal then condition becomes true.	(a != b) is true.
<>	Checks if the values of two operands are equal or not, if values are not equal then condition becomes true.	(a <> b) is true.
>	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.
<	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.
>=	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.
<=	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.
!<	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.
!>	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.

logical operators in sql

LOGICAL OPERATORS?
ALL	    (TRUE if all of the subquery values meet the condition)	
AND	    (TRUE if all the conditions separated by AND is TRUE)	
ANY	    (TRUE if any of the subquery values meet the condition)	
BETWEEN	(TRUE if the operand is within the range of comparisons)	
EXISTS	(TRUE if the subquery returns one or more records)
IN	    TRUE if the operand is equal to one of a list of expressions)	
LIKE	(TRUE if the operand matches a pattern)	
NOT	    (Displays a record if the condition(s) is NOT TRUE)	
OR	    (TRUE if any of the conditions separated by OR is TRUE)	
SOME	(TRUE if any of the subquery values meet the condition)

SQL AND Operator

SELECT first_name, last_name
FROM Customers
WHERE country = 'USA' AND last_name = 'Doe';

sql and

Used to join separate conditions within a WHERE clause.
Example: Returns events located in London, United Kingdom
SELECT * FROM events
WHERE host_country='United Kingdom' AND host_
city='London';

sql and or

AND (
  f.termination_date IS NULL
  OR 
  f.termination_date > CURRENT_DATE
)

SQL OR Operator

SELECT first_name, last_name
FROM Customers
WHERE country = 'USA' OR last_name = 'Doe';

what is in operator in sql

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