mysql

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mysql:----

sql:---structured query language

it allows to access and manipulate data.

RDBMS:--

Relational database management system(2 table)

architure:--

enrollment table:--

student_enrollno(pk) student_name student_course student_address

student table:--

student_enrollno(fk) student_name student_course student_atendance

library table:--

student_enrollno(fk)  student_name book_name  book_isue_date

join table.....

select* from tables...

the data in Rdbms  is stored in objects called table.

Table:-

A table is a collection of related data entries and it consists

of columns and rows.

sqlqueries:---

DDL:---

data defination language...

create,alter,drop

DML:--

data manipulation language...

insert,update,delete

Dcl:--

data control language

grant,revoke

Tcl:---

transaction control language

commit,rollaback,savepoint

//.........

create database datbasename

use databasename

create table employee_records(employee_id int(10),employee_name 

varchar(32)............);

///insert into employee_records(employee_id,employee_name,...)

values(1,'abc'........);

count how many manger in your table:--

select count(employee_id) from employee_record

 where employee_designation="manager"

 

find min salary person name with all records

find max salry person name with all records

find sum of the salary

find avg of the salary

find no of records in the table:--

select count(employee_id) from employee_record;

find no of manager in the table:-

select count(employee_id) from employee_record WHERE

employee_designation="manager"

find min salary:

select min(employee_salary) from employee_record;

find max salary:-

select max(employee_salary) from employee_record

find avg salary:--

select avg(employee_salary) from employee_record

find sum salary:--

select sum(employee_salary) from employee_record

Group by:--

......................

select count(employee_id),employee_designation from employee_record GROUP BY employee_designation;

....................

select count(employee_id),employee_designation,employee_name from 

employee_record GROUP BY employee_designation DESC;

....................

Group by and having clause:.

....................

list the number of employee_desiganation in each employee

dessignation .only include designation with more

than 1 designation.

select count(employee_id),employee_designation

from employee_record GROUP BY employee_designation having count(employee_id)>1;

.........................

select count(employee_id),employee_designation

from employee_record GROUP BY employee_designation having 

count(employee_id)>2;

..............................

Like operator:---

it is used in a where clause to serach for a specific pattern

there are two wildcards used  in conjuction  

with the like operator

1 % represent zero ,one or multiple char

2_ represent one single character

find all data from the table which has employee_designation 

started with character m...

select * from employee_record 

where employee_designation like 'm%'

1...search box:--text box button.....table all data of a name

search box  key press  a all data show(a)

find the data which has min salary in the table..

full join:--

/*directly not supported by mysql*/

SELECT id,name

FROM student_record

FULL OUTER JOIN teacher_records ON 

teacher_records.id= student_record.id;

/*we have to use union operator*/

Left join

SELECT *

FROM student_record

LEFT JOIN teacher_records ON 

teacher_records.id= student_record.id;

Right:

SELECT *

FROM student_record

RIGHT JOIN teacher_records ON 

teacher_records.id= student_record.id;

/*full*/

SELECT *

FROM student_record

LEFT OUTER JOIN teacher_records ON 

teacher_records.id= student_record.id

UNION

SELECT *

FROM student_record

RIGHT OUTER JOIN teacher_records ON 

teacher_records.id= student_record.id;

*///////.......*/

cross join:-

SELECT *

FROM student_record CROSS JOIN 

teacher_records

self join:-

SELECT a.id, b.name

FROM student_record a, student_record b

WHERE a.id = b.id;