how to create a primary key in a table

hello friends
today i will tell you how to create a primary key in your table
friends to know any person in any company it is difficult  task to search a particular person
because there are so many person who's name as same name .. suppose you want find a name whose name rakesh sharma
so you wrote following code assume
 select * from employ where name='rakesh sharma'

so you will see so many rakesh sharma there


but you want to see particular rakesh sharma detail who is working with administrative department


so you will write following code:-


select * from employ where desitinationid ='101'

primary key is use to find a particular record with a primary key you record every table identify uniquly


Thank you

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