**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.

**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 columns.it 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 clause.it will apply some aggregate condition to the data.

```
select movie avg(rating) from movie group by movies having avg(rating)>6
```

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.