Tech Junkie Blog - Real World Tutorials, Happy Coding!: DBMS

Showing posts with label DBMS. Show all posts

Friday, May 28, 2021

SQL Server : Installing AdventureWorks Sample Databases from Microsoft

1. Type in the following URL into your browser's address bar

AdventureWorks Database Download

2. Click on the "Download" button on page

Tuesday, May 25, 2021

SQL: The NOT IN Operator

The NOT IN operator in SQL means that you are retrieving records in the database that does not match the values in a comma separated list. In other words it retrieves the inverse of the IN statement by itself. Here is an example of how you can use the IN operator in the products table in the Northwind database.

SELECT * 
FROM Products
WHERE SupplierID NOT IN (1,2)

The above example all the products will be retrieved except for products with SupplierID of 1 or 2, here are the results

SQL: The IN Operator

The IN operator in SQL means that you are retrieving records in the database that matches the values in a comma separated list. Here is an example of how you can use the IN operator in the products table in the Northwind database.

SELECT * 
FROM Products
WHERE SupplierID IN (1,2)

In the above example all the products with the SupplierID of 1 or 2 are retrieved.

Sunday, June 19, 2016

SQL: Using Parentheses To Get Expected Result

SQL Server as well as other DBMS has an order of evaluation that can throw you off. Especially when you have more than one comparison in the WHERE clause. In this example I will show you the difference between using a parentheses and not using one, and how by using parentheses can give the results that you want. Suppose you want to get the products with CategoryID 1 and 2 that are priced less than 15 dollars in the Products table in the Northwind database. Here is the query without the parentheses:

SELECT CategoryID,ProductName,UnitPrice
FROM Products
WHERE CategoryID = 1 OR CategoryID =2 AND UnitPrice < 15

When you run the query above you would expect that all the records retrieved will have a unit price of less than $15 dollar but that is not the case. Below is the result from the query.

Friday, May 28, 2021

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