Coding

1. Structured Query Language
Prepared By:
Reema Agrawal
Asst Professor
MERI

2. SQL
 Structured Query language is a language that
provides an interface to database systems.
 SQL was developed by IBM in 1970.

3. Features Of SQL:
 SQL can be used by a range of users, including
those with little or no programming experience.
 It reduces the amount of time required for
creating and maintaining systems.
 It is an English like language.

4. Data types:
 SQL data type is an attribute that specifies type
of data of any object.
 Each column, variable and expression has
related data type in SQL.
 These are of several forms and sizes

5. Data types:
 Char- Maximum length of 255 characters. Alphabets
only.
 Varchar- Maximum of 8,000 characters.
Alphanumeric
 Int- Numeric and negative
 Float- Numeric, decimal and negative integers
 Number- It is of floating type. Number (P,S). P-
determines the maximum length of the data.
S- Number of places to the right of the decimal.

6. CREATE DATABASE
 Create DATABASE databasename;

7. The CREATE TABLE command
 The CREATE TABLE command defines each
column of the table uniquely.
 Each column has a minimum of three attributes
– a name, datatype and size.
 Each table column definition is separated from
the other by a comma.
 Finally, the SQL statement is terminated with a
semi colon.

8. The CREATE TABLE command
Syntax:
CREATE TABLE table_name
(
column_name1 data_type(size),
column_name2 data_type(size),
column_name3 data_type(size),
....
);

9. Inserting Data Into Tables
 Once a table is created, the most natural thing to
do is load this table with data to be manipulated
later.
Syntax:
INSERT INTO <tablename> values (<‘expression
1’>, <‘expression2’>);
For specific columns:
INSERT INTO <tablename> (<columnname1>,
<columnname2>)
values (<‘expression 1’>, <‘expression2’>);

10. Table Name: Employee
Emp_ID Name Designation Location Salary
A10141 Ajay Manager Delhi 75000
A10142 Rahul Executive Delhi 55000
A10143 Shruti Manager Bangalore 80000
A10144 Lokesh VP Bangalore 100000
A10145 Tripti Sales Mumbai 40000

11. Table Name: Student
Student_Rol
l No
Name Course Location Total Marks
10126734 Rahul BBA Delhi 500
10117834 Tarun BBA Delhi 586
10128734 Shruti MBA Delhi 540
10118834 Lalit BCA Delhi 523
10126834 Ajay BBA Delhi 596
10118934 Parul MBA Delhi 561

12. Viewing Data In the Tables:
 Once the data has been inserted into a table, the
next logical operation would be to view what has
been inserted.
 The SELECT command is used to retrieve rows
selected from one or more tables.
 To view the whole table
 Selected columns and all rows
 Selected rows and all columns
 Selected columns and selected rows

13. Viewing Data In the Tables:
 To view the whole table:
Syntax:
SELECT * FROM <tablename>;
• To view selected columns and all rows
Syntax:
SELECT <columnname1>, <columnname2> FROM
<tablename>;

14. Viewing Data In the Tables:
 Selected rows and all columns
Syntax:
SELECT * FROM <tablename> WHERE <condition>;
• Selected rows and selected columns
Syntax:
SELECT <columnname1>, <columnname2> FROM
<Tablename> WHERE <condition> ;

15. Eliminating Duplicate Rows
 Specific columns
SELECT DISTINCT <columnname1>,
<columnname2> from <tablename>;
 Entire rows
SELECT DISTINCT * from <tablename>;

16. Sorting Data In a table
 The rows retrieved from the table will be sorted
in either ascending or descending order
depending on the condition specified in the
SELECT sentence.
Syntax:
Select * from <Tablename> order by
<columnname1>;
Select * from <Tablename> order by
<columnname1>desc;

17. DELETE OPERATION
 The DELETE in SQL is used to remove either all
the rows from a table or a set of rows of a table.
 All the rows:
Syntax:
DELETE FROM <TableName>;
• A set of rows from table:
Syntax:
DELETE FROM <TableName> WHERE <condition>;

18. ALTER TABLE
 Adding new columns
ALTER TABLE <tablename>
ADD(<newcolumnname><datatype> (<size>),
<newcolumnname><datatype> (<size>));
 Dropping column
ALTER TABLE <tablename> DROP COLUMN
<columnname>;
 Modifying columns
ALTER TABLE <tablename> MODIFY
(<columnname> <Newdatatype>(<Newsize>));

19. Updating The contents Of a table:
 The UPDATE command is used to change or
modify data values in a table.
 All the rows:
UPDATE <TableName> SET
<columnname1>=<expression1>,
<columnname2>=<expression2>;
• A selected set of rows
UPDATE <TableName> SET
<columnname1>=<expression1>,
<columnname2>=<expression2> where
<condition>;

20. Renaming, Truncating And
Dropping Tables:
 Renaming tables:
RENAME <TableName> to <NewTableName>;
• Truncating tables:
TRUNCATE TABLE <TableName>;
• Dropping tables:
DROP TABLE <TableName>;

21. Some Queries:
 SELECT * FROM student WHERE name LIKE '%John%‘
(with either first or last name as JOHN)
 SELECT * FROM student WHERE name LIKE 'John%‘
(with first name JOHN)
 SELECT * FROM student WHERE name LIKE '%John‘
(with last name JOHN)
 SELECT * FROM student WHERE name LIKE '%a%' AND
name LIKE '%e%‘ (with either first alphabet as a or e)