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Page 31 - Modular_V2.0_SQL_Flipbook
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    Relational Operators

                     Consider the value of a=10 and b=5 to understand examples in the following table:

                             Operator                            Description                              Example
                                             Checks if value of ‘a’ is equal to value of ‘b’. If yes,
                                 =                                                                     (a = b) is false
                                             condition becomes true, else false.

                                             Checks is value of ‘a’ is not equal to value of ‘b’. If
                                 !=                                                                    (a != b) is true
                                             yes, condition becomes true, else false.
                                             Checks if value of ‘a’ is not equal to value of 'b'. If
                                <>                                                                     (a <> b) is true
                                             yes, condition becomes true, else false.
                                             Checks if value of ‘a’ is less than value of ‘b’. If yes,
                                 <                                                                     (a < b) is false
                                             condition becomes true, else false.

                                             Checks if value of ‘a’ is greater than value of ‘b’. If
                                 >                                                                      (a > b) is true
                                             yes, condition becomes true, else false.
                                             Checks if value of ‘a’ is less than or equal to the value
                                <=                                                                     (a <= b) is false
                                             of ‘b’. If yes, condition becomes true, else false.

                                             Checks if value of ‘a’ is greater than or equal to the
                                >=                                                                     (a >= b) is true
                                             value of ‘b’. If yes, condition becomes true, else false.

                     Boolean Operators

                     SQL provides the following Boolean operators:

                         Operator                   Description                                  Example

                                     It returns true if both Boolean expressions  SELECT * FROM employee WHERE
                           AND
                                     are true.                                    department = ‘IT’ AND age = 28;

                                     It returns true if  either of the Boolean  SELECT * FROM employee WHERE
                            OR
                                     expressions is true.                         age = 25 OR age = 26;
                                     It reverses the value of any other Boolean
                                                                                  SELECT * FROM employee WHERE
                           NOT       operator, it means it returns a false if the
                                                                                  department = ‘IT’ AND NOT age = 28;
                                     expression gives a true and vice versa.
                     Special Operators

                     The different special operators in SQL are as follows:

                       Operator                                          Description
                          ALL       This operator returns TRUE if all of the subquery values meet the condition.

                          ANY       This operator returns TRUE if any of the subquery values meet the condition.

                                    This operator is used to indicate a range which otherwise is done using relational
                       BETWEEN
                                    operator.

                         EXISTS     This operator returns TRUE if the subquery returns one or more records.

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                                                                                              Handling Records in MySQL

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