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

Sometimes a row or an object will not contain any value (`NULL`), and we must handle such cases properly. For example, we might want to check whether a value is `NULL` and replace it with another value. T-SQL provides `ISNULL()` and `COALESCE()` methods for this purpose.

## The `ISNULL()` function

This function checks whether a value is `NULL`. If it is `NULL`, then the function returns the value that is passed as the second parameter. Otherwise, the function returns the first value:

```SQL
ISNULL([Value to check], [Value to return if NULL])
```

Let’s consider the following `Profiles` table.


Sometimes a row or an object will not contain any value (`NULL`), and we must handle such cases properly. For example, we might want to check whether a value is `NULL` and replace it with another value. T-SQL provides `ISNULL()` and `COALESCE()` methods for this purpose.

# The `ISNULL()` function

This function checks whether a value is `NULL`. If it is `NULL`, then the function returns the value that is passed as the second parameter. Otherwise, the function returns the first value:

```SQL
ISNULL([Value to check], [Value to return if NULL])
```

Let’s consider the following `Profiles` table.


Learn how to handle NULL values in T-SQL.

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

Handling NULL

The `ISNULL()` function