Viewing data in the tables

VIEW ALL ROWS AND COLUMNS:

• The select commands used to view all columns and rows.
• Syntax
• select * from
• Example:
• select * from student;

VIEW SPECIFIC COLUMNS:

• The select commands used to view specific column data.
• We can specify the list of columns with select command.
• All columns names can be separated by comma.
• Syntax
• select from
• Example:
• select rollno, name from student;

CONDITIONAL RETRIEVAL:

• The select commands used to retrieve specific rows fro table.
• To filtering the records we can use where clause.
• Syntax
• select * / from where
• Example:
• select rollno, name from student where city='Delhi';

REMOVING DUPLICATE ROWS:

• The distinct command used to remove duplicate rows.
• Syntax
• select distinct * / from
• Example:
• select distinct city from student;

VIEWING STRUCTURE OF TABLE:

• DESC stands for DESCRIBE
• DESC command is used to view the structure of the table.
• This commands display the structure of table with all columns.
• Each column contains the name, data type, and size of columns.
• Syntax
• DESC
• DESCRIBE
• Example:
• DESC Student
• DESCRIBE Student

INSERTING DATA INTO TABLE:

• Insert command is used to insert records into a table.
• Using insert command, you can insert records of values for all columns or specified columns.
• Syntax
• insert into [(column_name1,column_name2,...)] values (exp1, exp2, exp3);
• Example:
• insert into student values(2,'Sarthak','Ganpat Uni','Kherwa','31-Aug-12');
• insert into student(rollno,name) values(3,'Anita');
• Rules:
• They must be the same type.
• They must stay within the limits of their particular column size.
• There must be a one to one correspondence between selected columns.

INSERTING DATA INTO TABLE FROM ANOTHER TABLE:

• Insert command is used to insert records into table from another table.
• Syntax
• insert into [(column_name1,column_name2,...)] select from ;
• Example:
• insert into stud as select rollno, name from student;

INSERTING DATA INTERACTIVELY:

• '&' symbol is used to insert data interactively.
• This symbol indicates to oracle that you want to specify a value for that column before oracle processes query.
• Syntax:
• insert into values [(column_name1, column_name2,...) values(&var1, &var2,....)
• Example:
• insert into student values(&rollno, '&name','&address','&city','&DOB');

Note: To enter characters or string or data or time values must be enclosed by a single quote before and after.