Select statement can perform two types of job Selection Projection  Column wise projection Row wise projection Selection It means select all data from table and not apply any clause. Ex: SELECT * FROM student; Projection - Column wise Projection Column restriction is a concept through which those many attributes are displayed which are mentioned in the select statement Ex: SELECT Name, Mobile FROM student; Projection - Row wise Projection Row restriction is a concept through which those many records are displayed where condition is satisfied. Ex: SELECT Name, Mobile FROM student WHERE ID = 5; Column Alias Column alias is concept through which user can provide duplicate name to an existing column. It can be given using three different methods Type-1 SELECT Name Name, Mobile Mobile FROM student; Type-2 SELECT Name 'Name', Mobile 'Name' FROM student; Type-3 SELECT Name as 'Student Name', Mobile as 'Mobile Name' FROM student; Column Concatenation Column

Select <exp> From <t_name> [where<cond>] [group<col_name>] [having by <group col_name>] [order by <col_name>[asc|desc]];

Ø Data : It is raw fact through which an object can‘t be identified. Ex – employee no. name, salary of an employee are individually known as one one data Ø Information Organized collection of related data is known as information through which an object can be clearly identified. It is raw fact through which an object can be identified. Ex – employee no. name, salary of an employee are individually known as one one data Ø Data file Organized collection of related information is known as a data file. Ex – sales dept, purchase dept, admin dept of a particular company individually maintains their data file. NOTE Through data is a raw fact through which an object can‘t be identified but it minimum requirement of data base. Ø Why data base ? Data is maintained to keep track on object day to day traction. The advantage of data base management is to know assets / liability, profile /loss of an organization. Database has no scope that means it can be implemented on small scale corporate house.

 “It is a concept or a mech. Implemented on select statement to extract data from multiple tables.” To extract date from multiple tables the table must have a relation and depending on the relation join is categories in 4 diff types. 1.             Equijoin 2.             Non equijoin 3.             Self or inner join 4.             Outer join EQUI JOIN:         It is a type of join which will extract date from multiple tables won is available. Emp                                                                                          Emp no      Name        Sal       Dept no         Xid          1         X         2300         20         X1         2         Y         2500         10         X2         3         Z         3600         20         X3         4         Aa               9300         30         X4         5         Bb         6300         10         X5 Dept       Dept no        Dname          Loc