How to Get Data from a SQL Database and Table Using the SELECT Function!

hello welcome back to the channel today's episode is going to be uh part two of our intro to sql tutorial series and today specifically we'll be looking at how to use the select statement inside of microsoft sql server and the microsoft sql server management studio so if you haven't downloaded or gotten started with sql yet i recommend you check out the previous video otherwise if you're just here to get some knowledge on the select statement then let's get right into it so the standard method for pulling data out of tables in sql is using their select statement and comboing that with a from statement that's going to tell you what table to grab it from so let's go ahead and look at this employee table that i've already made we have six employees in here a position that they work and then the salary that they currently get paid this is fairly standard data that you might keep in a table and typically in sql these tables get a lot more rows and a lot more columns and a lot more complicated but we've got a nice basic one here for learning how to use the select statement so let's just start by saying we want to grab everything out of a table we just want to see everything that's in a table uh sql has their special character for that is the star or the asterisk for selecting everything so if we go ahead and say select everything from the employee table and then execute this we see in our results here okay we've got all three columns we've got the employee name their position worked and their salary at the company just by using the star so that's useful but let's say we just want one of these columns we just want to know the employee name because currently we're just trying to make a list of the employee name well you can type in the specific column name you see at the top of the columns you can type in the specific column name that you want to see and then run it again and you'll have just the employee name the important thing to know is if later in your query you want to manipulate data now you have only grabbed the employee name so you can't use the salary unless you also reference the salary but so this works for multiple columns if we want to know the employee and their position but we don't want to know the salary it's private and we're just trying to show a list of our employees you separate your columns by a comma and then you run this again and you get employee and position there so that's pretty cool um it it it's not just two it works uh unlimited number of times you can go up to um you know however many columns you have but one thing that you should note is if you have a misspelling here it's going to tell you invalid comment com a column name and just not give you data back so if you use an external tool to create sql queries like you're writing from an in hmi for a customer system or a web interface and that's where you create a sql query it will just fail and return no data if you use an invalid column name which is why i like writing a lot of my queries for the first time in the management studio run it a few times see that it executes successfully and gives you the data back that you would be hoping for and then export it to whatever tool you actually use to pull the data um so uh really the the cool thing about the select is you can narrow down the data that you actually want to see but also what's important to think about is if you're just grabbing data certain data like just the salaries you have to think is this useful information when i structure a query because if you just pull salary and you don't know position or name or anything like that who's going to do what with this data so sometimes a person might say like oh i just need to see the average salary for an employee company that's fine you could limit it to this but most of the time if you're the one writing the sql queries you also have to do some thinking about what data would actually be useful for the person who's going to be reading this data so just that's a good way to think about how you structure your queries but really this is a nice short video we're just taking a look at the select statement the star will grab everything beyond that you want to reference specific columns and that's how you use the select statement within one table so that's it for today hope you found this useful feel free to leave any questions or comments you have on this in the comments below and if you found this or anything else on the channel useful i really appreciate a like and a subscribe it helps the channel a lot and as always thanks for watching and good luck with your code thanks bye