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Difference between char and varchar datatype: char: 1.char datypes is use for store chracter string of fixed length. 2.better performance than varchar varchar:1.varchar datype is used to store character string of variable length. 2. low performance than char create database: syntax:- create database database_name; for checking database: command: show databases; for work database command- use dattabase_name ------------------------------------------------------------------------------- create table: syntax: create table table_name( column1 datatype, column2 datatype, - - column3 datatype ); exa; show tables; --table check create table Employee( empid int, name varchar(30), salary int, dept varchar(20), gender char(2) ); desc Employee; - table describe ---------------------------------------------------------------------------------------- comments in sql: single line comment: -- comments multiline comment : /* statemets */ ---------------------------------------------------------------------------------------------------------------- insert value in table: the value provide in sequence and values required for all column syntax:- insert into tablename values(----) insert into Employee values(1,"ram",20000,"it","ma"); ------ sequence is not manadatory and missing values for column syntax: insert into table_name(column1,column2,-----columnn) values(value1,valu2,----valuen) ex;- insert into Employee(empid,name,salary,gender) values(1,"radhika",30000,'fe'); insert into Employee(name,empid,salary,gender) values("nikita",4,30000,'fe'); ---- multiple row insert at one time:- insert into Employee values(6,"ratna",20000,"hr","fe"),(7,'hari',3000,'finance','ma'), (8,'jiyu',50000,"IT","ma");
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