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find out database
command=> show databases;

create database:
syntax=> create database database_name;
create database second;

select working database
syntax:-use database_name;
=>use second

create table:
create table table_name(
      column1 datatype,
      column2  datatype,
      column3 datatype,
      column3 datatype

exa:-   create table Student(
           rno int, 
           name varchar(20), 
           address varchar(20),
          marks int, 
          gender char(1));

checking table:
show tables_name;
=> show Student;

for showing table structure:
syntax:desc tablename;
exa :-desc Student;

insrt data into table:
seuence is manadatory.
number of column =number of values
1- insert into tablename values(value1,value2,-----valueN);
exa:- insert into Student values(1,'nikki','pune',56,'male');

--sequence is manadory for column we given in insert stament
count of column specify into insert =number of values

no value for any column.
2.- insert into Tablename(column1,column2-----columnN) values(value1,value2,-----valueN);

ex:- insert into Student(rno,name,marks,gender) values(2,'nikita',70,'F');

multiple value insert at one time
syntax:- insert into tablename values(value1,value2,-----valueN),(value1,value2,-----valueN)-----(n);
exam:- insert into Student values(3,'ram','satara',67,'m'),

fetch all record from tables:-
selct * from tablename;
exam:-select * from Student;

fetch select column from table;
ex;- select name,marks from Student;

Contraints in sql:
contraints is use for to specify rules for the data in table.
1. NOT NULL:-ensure that the column cannot have a null values:
2.UNIQUE:-ensure that all values in a column are differents.
3.CHECK:-Ensures that the values in a columns satisfies a given specific condition.
4.DEFAULT:-set a default value if value is not specified for a column.
5.PRIMARY KEY:-ensure that  the values of column is NOT NULL and UNIQUE.

create table table_name(
           column1 datatype contraint,
           column2 datatype contraint,
           columnN datatype contraint

Drop command:-
for database:
 is used for delete the existing sql database.
syntax:- drop database Database_name
example:- drop database demo1;

for table:
drop table command is used for the table structure delete from database.

syntax:- drop table table_name
example:- drop table student;

truncate command:
is used for  delete the data from tables.
it is used for empty table.

syntax:-tuncate table tablename;
exa;- truncate table customer;

Difference between drop and trucate:
Drop :-1.Drop command is use for remove table defination /table structure from database.
       2. table does not exist in databse.

Truncate:-1.truncate command is used for delete all rows from tables.structure remain same.
          2.table is exist in databse.show empty table.


Create Customer table.
custid primary key,
name unique,
address not null
age age>18
gmail abc@g.com

insert minimum 10 records

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