Untitled

02/02/2024
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distinct keywords:
- the distinct is used for return only unique(diffrerent) value.
syntax: select distinct column from tablename
ex:
select name from employeeinfo;
select  distinct name from employeeinfo;
select  distinct name,salary from employeeinfo;

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Aggregate function:
1.count()
2.min()
3.max()
4.avg()
5.sum()


count()
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1.count(): return number of records with match specific criteria.
syntax: select count(columns) from tablename.
ex: select count(*) from employeeinfo;

select  count(distinct address) from employeeinfo;

select count(salary) from employeeinfo;
select count(distinct salary) from employeeinfo;