Hey guys, in this lesson we will be discussing how we go about selecting or viewing records in our database tables. Now in our previous video, we may have glimpsed the query that was used to select the records from our students table. But now we will actually do a breakdown and evaluate how this statement can be used. Now, the whole purpose of wanting to view the records could be maybe two reports. You know, the boss wants to know all the students in currently in the database and people have been registering for school online listener, you need to pull all the records off students so you can just go straight to the database and select those records and potentially export it to excel and give it to the higher ups for evaluation. So the statement to do this is quite simple and it is what you call a select statement.

So we select and then we want star meaning All all records all columns. And we say from. And then we specify our table name, which is students. Now, once again, we have to use our use statements to specify the database to be used in the context. All right. So once we do that, and we click Execute, then we see that we have a similar grid to what we would have seen when we wanted to add records using the workbench interface.

So it's the same view essentially. And more or less, this is the same query that we would have seen. Now the challenge might be that there are data elements here that are not necessarily, you know, conducive to the analysis of the data, meaning, you probably do want to see this auto incrementing ID value, and you probably don't need the enrollment ID. And so SQL allows us to spend sissified exact columns that we wish to see when we are selecting records. So start here essentially means give me all of the columns that are available to me. And just by clicking these columns down in this view, you see that it's actually sorting accordingly.

But anyway, that's aside from the point, we want to select specific columns for our query for or reports. So I can say select, and then I can specify the columns by name. So I want the last name. And I want the first name columns. And let's say I want Date of Birth also. And I can say select and individually list the columns or comma separated upon to the last one, which then leads into my from statements and then the table that I want them from which would be stupid.

And then with a semicolon, so I'm just going to execute this section by itself. So I'm just going to highlight it and click this with the cursor. And you see that this query results looks different from the previous one, because normally seeing those columns that that's specified, if I just execute the lightning bolt, it will execute both select queries, and allow us to view the results side by side. And we can view the real results side by side by just coming down here and we see students three students four. So for each select query that might be in the file, the results will be tabbed and separated like this. Alright, so this allows us this as an SQL allows us to specify which columns or data points exactly we want to see for each student.

So for student number one, we're seeing lastname firstname, data, birth enrollment, dates, and Id when we start Select star. But then over here, we don't know if it's student 123 or four, outside of the name, of course. But if the names weren't so specific are for testing, then you would have a greater challenge, knowing which one is student 123 or four granted student 123 or four, the ID numbers could be irrelevant to whoever actually is asking for these reports to be provided to them. Now, in the event that this should be a report, and you've written your query, you can always export to an external file, which is usually a CSV. Alright, so you can just see in the interface, you see the word export, and you see that icon, you click that, and then you can go ahead and save that file. So you will see that I already saved the file as dot CSV prior to this.

But I'm not very comfortable with how this query looks because even if I explain This CSV, my column names are not as much as I use the underscore to kind of separate the first and last name, they're still not as user friendly as I would like. So I would actually want to rename the columns so that my users who will be consuming the output of this query would have an easier time looking at the column headings and deciphering what is being represented. So I'm actually just going to break these lines quickly so that we can have each column in its own line. And then we're going to go through a whole we rename our columns. So to rename more columns, you can actually use a keyword called as, and then we can give it a value. So last name, but then of course, we discussed that we don't want to space AC last is a keyword and name is a keyword and my SQL just will not take kindly to this.

So whenever we want to use two words, we use our posture trophy, which on my us slash Western keyboard is the, it shares a button with the two there. And that is to the left of the number one button or the number one key to the top left hand corner on the escape. So that is the apostrophe, not the single quote, but the apostrophe. Alright, so we have last name as, and then we use the apostrophe and whatever we type in there will not be the column name. So if I execute this quickly, then we can see this being demonstrated where last name no looks like Standard English last space name, first name and date of birth also need to be fixed. So I'm actually going to do this but I don't need the keyword as so you can actually just forego the use of the keyword as and to say first name, and date of birth in the same way, we just use the apostrophe date of birth.

Then I'm just going to re execute this query. And then we see, and I'm just going to find in the columns so that everything looks good. And then we see that last name, first name, date of birth. So for any column that you are entering into your database, you don't want to use a space, I don't recommend that user space. So it's either going to make it one word camelcase, or use an underscore. But when you're presenting the data in a in an Excel spreadsheet to make life easier, you can just rename the columns from the query side.

And then when you export those renamed, headings will go with the data. So those are the ways that you can go about selecting data. And once again, once you've run that query and extracted the data that is required, you can always just export it to a CSV file which can be later opened in Microsoft Excel or comparable tool. analyzed accordingly. So, once again, I'll include this script file with the resources for this video.