Null Operator : It is a very special operator in Sql server.The NULL operator is used to compare a value with NULL value. Ex: Select * from employee where comm is NULL; The above statement only return those many employees are not getting commission from company. NOT Operator: It is used for negative statement. The NOT operator reverses the meaning of the logical operator with which it is used. Ex: Select * from employee where comm IS NOT NULL; The above statement only return those many employees are getting commission from company. EXISTS: The EXISTS operator is used to search for the presence of a row in a specified table that meets certain criteria. Ex: IF EXISTS (Select 1 from employee where name like '%N%') Block 1 ELSE Block2 IN: The IN operator is used to compare a value to a list of literal values that have been specified. Ex: Select * from employee where Location IN ('Bangalore', 'Bhubaneswar', 'Mumbai'); The above statement only return those man

PL/SQL identifiers are constants, variables, exceptions, procedures, cursors, and reserved words. The identifiers consist of a letter optionally followed by more letters, numerals, dollar signs, underscores, and number signs and should not exceed 30 characters. By default, identifiers are not case-sensitive. So you can use integer or INTEGER to represent a numeric value. You cannot use a reserved keyword as an identifier.

DML is also known as RML, which is Responsible to manipulated language, the records of table and statements are given below Insert, update, delete Syntax for insert Insert into <t_name> [(col1, col2, col3,….N) Values (value1, value2, value3……..N); Above syntax is syntax of data insertion using column list. User has only remembered name of column not the sequence. Insert NULL value in a column NULL value can be assigned in a particular column in two different manners. è   Explicitly using NULL keyword è   Implicitly using column list Ex Insert into sysemp6 Values (2,BBB,NULL,’manger’); Insert into sysemp6(empno,job, name) Values (3,’manger’, ‘CCC’); NOTE: User is not allowed null value a column explicitly or implicitly if column explicitly, if column is protected with not null constraint. Data insertion using substation variable Ex Insert into sysemp6 Values(&empno,’&name’,&salary,’&job’); Syntax record using update Update<T_name> Set col_name=<value>[c

Where clause must have one condition statement in Select statement. To restrict depending upon condition min requirement is an operator. 1. Relation Operator 2. Logical Operator 3. Arithmetic Operator 1. Relation Operator : Operator Times of use = (Equals) Equal to > (Greater Than) Greater than < (Less Than) Less than >= (Greater Than or Equal To) Greater than or equal to <= (Less Than or Equal To) Less than or equal to != (Not Equal To) Not Equal To <> (Not Equal To) Not equal to (not ISO standard) !> (Not Greater Than) Not greater than (not ISO standard) !< (Not Less Than) Not less than (not ISO standard) Ex: SELECT * FROM employee where salary >