Limit Offset | Alter | OrderBy | Aggregate Function | GroupBy | Having | Keys | Primary | Foreign | JOIN

Limit Offset | Alter | OrderBy | Aggregate Function | GroupBy | Having | Keys | Primary | Foreign | JOIN


Alias: alias used “as” which gives printed value to given coloumn name.

Order By: order by is used to make table coloumn in the specific order either in the assending order or descending order.
Aggregate Function: there are five aggargate function which provide better performance to the databases.
These are:
Count(): this will count the no. of the rows in the table.
sum(): this will gives you sum of integer colomn value.
max(): this is used for calculating the maximum value in the coloumn.
avg(): this is used for calculating the average value of the coloumn.
min(): this is used for calculating the minimum value in the coloumn.
Group By: group by used for the a group of category which is also used the aggregate function on this group of category.
Having: having used on this grouped data which is also used this aggregate function. Simply in other words it is used to make operation on this grouped data.

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OrderBy:it is used to group the column in particular order according to Int values and ascending and descending order

select * from employee order by <column name>

Aggregate function:
1.count:To get the count of the rows->select count(id) from <table name>
2.sum:To get the sum value of the column->select sum(salary) from <table name>
3.avg:To get the average value of the column->select avg(salary) from <table name>
4.max:To get the maximum value of the column->select max(salary) from <table name>
5.min:To get the minimum value of the column->select min(salary) as min_sales from <table name>
GroupBy:it is used to group the rows from table based on one or more also can used to calculate aggregate function by column.

select product ,avg(sales) from product group by product;

Having:it is used to filter the result of query that includes groupby will apply some aggregate condition to the data.

select movie avg(rating) from movie group by movies having avg(rating)>6
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alias = we use this for printed value to given column name and we use this “as” keywords.
order by = its use for create table column ascending order or descending order.
aggregate function = 5 function =>
1. count() = its for count rows
2. max() = calculating max value in column
3. min() = calculating min value in column
4. sum() = its gives us sum of number values
5. avg() = its calculate average value in the column
having = its used for grouped data operation , and its apply aggregate condiction to data.

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