Gain insights into T-SQL syntax, table creation, data manipulation, and relationships. Delve into advanced constructs like stored procedures, functions, and triggers to enhance your database development skills.

tsql.tar.gz

T-SQL-SPA

T-SQL is a dialect of SQL that is used in Microsoft SQL Server. The popularity of Microsoft's database management system sustains high market demand for people well versed in T-SQL. 

This course teaches the core concepts and syntax of T-SQL. First, you will learn how to create tables, insert data, update existing records, and create relationships between tables. Then, you will be exposed to more advanced constructs of T-SQL, like stored procedures, functions, and triggers. 

By the end of the course, you will be sufficiently adept with T-SQL and be able to perform your day-to-day tasks as software and database developers effectively.

Querying Databases Using Transact-SQL

An **aggregate function** is a function that takes in multiple values and returns a single value. It can be viewed as a function that performs an operation over the values of multiple rows.


In T-SQL, we have these aggregate functions:

- `AVG()`: Returns the average of supplied values
- `COUNT()`: Returns the number of rows
- `MIN()`: Returns the minimum value
- `MAX()`: Returns the maximum value
- `SUM()`: Returns the sum

As an argument, all aggregate functions take an expression that returns a range of values. Often, the expression is the name of the column over the values of which we want to perform the operation:

```SQL
SELECT AVG(ColumnName) AS Average
FROM TableSchema.TableName;
```

The `AVG()` and `SUM()` functions accept only numeric columns, while `MIN()`, `MAX()`, and `COUNT()` functions can accept numbers, text, and datetime columns.

## Calculate the average

If we supply a range of numeric values, the `AVG()` returns the average. We often use the `AVG()` function to calculate the average of a particular column. Let's calculate the average grade of students:



An **aggregate function** is a function that takes in multiple values and returns a single value. It can be viewed as a function that performs an operation over the values of multiple rows.


In T-SQL, we have these aggregate functions:

- `AVG()`: Returns the average of supplied values
- `COUNT()`: Returns the number of rows
- `MIN()`: Returns the minimum value
- `MAX()`: Returns the maximum value
- `SUM()`: Returns the sum

As an argument, all aggregate functions take an expression that returns a range of values. Often, the expression is the name of the column over the values of which we want to perform the operation:

```SQL
SELECT AVG(ColumnName) AS Average
FROM TableSchema.TableName;
```

The `AVG()` and `SUM()` functions accept only numeric columns, while `MIN()`, `MAX()`, and `COUNT()` functions can accept numbers, text, and datetime columns.

# Calculate the average

If we supply a range of numeric values, the `AVG()` returns the average. We often use the `AVG()` function to calculate the average of a particular column. Let's calculate the average grade of students:



Learn about SQL functions that take multiple values as input.


Aggregate Functions

Learn about SQL functions that take multiple values as input.

Before We Start

T-SQL Basics

Querying Multiple Tables

Grouping and Aggregation

Subqueries

T-SQL Fundamentals Assessment

Built-in Functions

T-SQL Programming Basics

Additional Programming Constructs

Course Comprehension Assessment

Conclusion

Aggregate Functions