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## What are aggregate and scalar function in SQL?

**Aggregate functions operate against a collection of values and return a single summarizing value**. Scalar functions return a single value based on scalar input arguments. Some scalar functions, such as CURRENT_TIME, do not require any arguments.

## What is aggregate function in SQL with example?

SQL aggregation is the task of collecting a set of values to return a single value. It is done with the help of aggregate functions, such as **SUM, COUNT, and AVG**. For example, in a database of products, you might want to calculate the average price of the whole inventory.

## What are scalar functions in SQL example?

Scalar SQL Functions

Function | Description |
---|---|

LEN() | Returns the length of the text values in the column. |

MID() | Extracts substrings in SQL from column values having String data type. |

ROUND() | Rounds off a numeric value to the nearest integer. |

NOW() | This function is used to return the current system date and time. |

## What is the difference between scalar and aggregate functions?

Aggregate and Scalar functions both **return a single value** but Scalar functions operate based on a single input value argument while Aggregate functions operate on a single input set of values (a collection or column name).

## What is scalar query?

A scalar query is **a query that returns one row consisting of one column**.

## What is scalar aggregate?

The scalar aggregate, avg(avg(price)), is **the average of the average prices by type in the titles table**. In standard SQL, when a select list includes an aggregate, all the select list columns must either have aggregate functions applied to them or be in the group by list.

## What is difference between stored procedure and function?

The function must return a value but in Stored Procedure it is **optional**. Even a procedure can return zero or n values. Functions can have only input parameters for it whereas Procedures can have input or output parameters. Functions can be called from Procedure whereas Procedures cannot be called from a Function.

## Which is the aggregate function?

An aggregate function is **a mathematical computation involving a range of values** that results in just a single value expressing the significance of the accumulated data it is derived from. Aggregate functions are often used to derive descriptive statistics.

## What is the use of aggregate function?

An aggregate function **performs a calculation on a set of values, and returns a single value**. Except for COUNT(*) , aggregate functions ignore null values. Aggregate functions are often used with the GROUP BY clause of the SELECT statement.

## What is an aggregate query?

An aggregate query is **a method of deriving group and subgroup data by analysis of a set of individual data entries**. The term is frequently used by database developers and database administrators. … The term “aggregate query” is quite common in nearly all database software documentation.