If you're looking to learn the basics of PostgresQL or SQL in general, you've come to the right place. This is the first video in a series of videos that will teach you how to get started with SQL using the PostgresQL database. In this video, you'll learn how to open the software to access the PostgresQL database, create your first table, add some data to the table, and see the data that you added. The first step is to install the PostgresQL database. If you've already got this installed, that's great. If not, I've got separate videos on how to set it up, as there are a few different ways and you can install it on Windows, Mac, or Linux. So, rather than put the installation in this video, I've linked the installation videos below, so you can go and follow those steps and resume this video. As part of the installation of the PostgresQL database, a tool called PG Admin is installed. This tool is called an SQL IDE or SQL Editor and allows you to access the database and write the code that works with the database. We'll be working with this PG Admin tool for this video. Also, the PostgresQL database is often called Postgres for short, so I'll use these terms interchangeably in this video. Let's get started. We can begin by opening the PG Admin application. On Windows, this should be in the Start menu. On Mac OS, you can find it in the Applications folder or search for it using Spotlight. The PG Admin application works in the same way on all operating systems. Once you open PG Admin, you'll be prompted to enter a master password. This is something that you specified when you installed the PostgresQL database, so you'll need to enter it here to work with PG Admin. Enter the password and click OK. If you're not sure what the master password is or entered incorrectly, the only way I believe to get around this is to uninstall and reinstall the Postgres database again. Check the description and comments for more information if you're in this situation. Once you've entered the master password, PG Admin will open. The main screen of PG Admin looks like this. Along the top is the toolbar with menus and buttons. On the left is a panel with a label of servers at the top. The majority of the screen is the working area, which we will see more of soon. The first thing to do once we have opened PG Admin is to connect to our database. This will let us work with the database and start writing SQL code. In PG Admin, a database connection is called a server, and there should have been one created when you installed Postgres. Click on the triangle next to the server's item on the left, and it should expand with one entry underneath. In my PG Admin, I have several servers created, as I've been using PG Admin for a while for different things. But you should only see one entry here, called Postgres 14, or whatever version of Postgres that you installed. The icon will have a red X next to it, as you can see here. Double click on it, and within a couple of seconds it should change the Postgres logo and expand to the next level of items. Congratulations, you have successfully connected to a Postgres database server. If you get any errors with this or don't see anything in the service section, look at the comments below this video for some tips or solutions. After you have connected to the Postgres server, you'll see an entry in the left panel underneath the server called databases. Click on the arrow to expand this entry. In my example, there are three databases, gravity books, Postgres, and Skylight. Your server should only have one, called Postgres. This is the default database, and will be enough for this lesson. The first thing we want to do once we have connected to our database server is to create a table. A table is an object on a database that contains data. It's the fundamental piece of the database. Creating a table will mean that we have somewhere to store data and view that data. To do this, we can write some SQL code. We'll need a place to write that SQL code though. In PGE admin, click on the first icon on the left of the toolbar called Query tool. Once you do, a new tab appears in the main section of the screen. The main part of the screen changes to a white background with a blinking cursor. The heading of the tab shows the name Postgres, slash Postgres at Postgres QL14. This means we are on a Postgres server, and the name of the database is Postgres. This is OK. The main part of the window here is where we want to focus. This is where we write a SQL code. Let's write our first SQL statement. We'll write some SQL to create a table. To do this, we write the command create table. SQL is not a case sensitive language. You can write this in uppercase, lower case, or any other combination. If you've seen examples of SQL online, you might see some people prefer to write SQL in lower case and others in uppercase. Personally, I prefer to write this create table statement, which is also called an SQL keyword in uppercase. But if you prefer to write it in lower case, go ahead and do that. After you write create table, we need to specify the name of the new table to create. Let's say we are creating a table for our new ecommerce website, and the first table we want to create is for products. So we'll call a table name product. Add a space and then type the word product. You can call it products, the plural, instead if you prefer. It's a commonly debated topic in the world of SQL on whether you should name your table singular or plural. I usually prefer singular, but you can call it whatever you prefer. After the word product, we add an open round bracket. PG admin will automatically add a closing bracket, which is good. With the cursor in between the brackets, press enter a few times to add in some new blank rows. Move your cursor back to the first empty row here. Within our table, we need somewhere to store the data we want to put inside it. A table needs something called a column, which is a named piece of information within a table. Tables can and often have many columns, but it needs at least one column. It's like a spreadsheet. Without columns has no data, but if there are some columns, then you can add some data. For our example, we'll add two columns. So in the blank row here, we'll add a new column to this table. First, we specify the column name. Let's say we want to be able to recall the name of a product. So let's call a new column product underscore name. We can't use spaces in the name of a column, so we'll use an underscore instead. You'll notice here that I've added this product name column and the table name of product in lowercase. This is just personal preference, and you can use uppercase or lowercase if you prefer. You'll also notice that they are both in black font. This is because they are not SQL keywords. An SQL keyword is a built-in word in SQL that has a certain meaning, like create table, which is shown in a different color. The word product is not a keyword, so it's just shown in black. After the product name, we need to specify the data type of this column and its size. Why do we need to do this? Well, databases and the SQL language are very efficient, and one of the reasons is that the data stored in the database conforms to one of the preset types of data. Our product name is a text value. The data type that we can use in Postgres is called VARCHAR, which is short for varying character. So, enter the word VARCHAR. Then, enter an opening bracket. We need to specify the size of this column, or the number of characters. How many characters do we think we need for a product name? For this example, let's go with 200. The general advice for choosing a size of a VARCHAR column is to make sure it's big enough for the kind of values you expect, but you don't need to make it very big. After you enter 200 inside the brackets, move the cursor outside of this bracket and add a comma. This means we have finished specifying information for that column, and we want to add another. Press Enter to go to a new line, where we can specify our second column. Our second column will be called price, and we'll store the price of our product, so enter the name of price. We'll need to specify the data type for this as well. In this example, the price is a number, and more specifically a whole number, just to keep things simple. The data type for this in Postgres is called integer. So, use the data type of integer. We don't need to specify a size for the integer, because it comes with a default size. After you specify integer, we've finished with the price column. We don't need to add a comma, because we're not specifying any more columns. Finally, go to the end of the brackets for create table, and add a semicolon, which will indicate the end of a statement. After you've written the create table statement, it's time to run it. When we run it, the code will be executed, and the changes will be made to the database. In this example, the table will be created. To run your SQL statement, click on the execute button here, which is the triangle that looks like a play button. When you click this button, the bottom of the screen will show a messages tab, with the message of create table, and query returned successfully. This means your SQL statement has worked, and your table is created. If you get an error message, it could be for one of a few reasons. You could be missing a comma, or brackets in your query, or not added a space between a name and a data type, or some other reason in your code. Check that your SQL statement looks like the one in this video, and run it again. If you get an error that says, relation product already exists, this means you have attempted to create a table, but a table without name already exists. We can solve this by deleting the table, and running the SQL again. You can delete a table using the panel on the left of the screen. Expand the Postgres database, then schemas, then public, then tables. You should see a product table there. If not, right click on the tables folder, and select refresh. Right click on the product table that you see there, and select delete or drop. Click OK on the message that appears. You can then run the create table statement again, and it should be successful. Now that we have a table created, it's time to add some data to it. At the end of your create table statement, after the semicolon, press enter to add a couple of empty lines. Here we will write our next statement. The SQL keyword to use to add data to a table is called insert. So enter the word insert, and then enter. Then we specify the name of the table we want to insert data into. In our example, we want to add data to the product table, so enter the word product. After product, add an open bracket. Inside the brackets is where we specify the columns that we want to add data into. We want to add data to both the product name and price columns. So enter product name and price, separated by a comma, then a closing bracket. After the closing bracket, we can go to a new line and enter the word values. We don't need to go to a new line, but it helps to make our code readable if we split up our statements like this. After the word values, we open some brackets. Inside the brackets is where we specify the actual values we want to put into the table. So what product do we want to add? We need to specify a value for the product name field first. Let's say we want to add a product called genes, so we enter a value of genes. Next, we want to specify the price, so let's add a value of 50. After the brackets, add a semicolon to the end of the statement. Our statement looks like this. Let's quickly execute button again to run our statement. We see at the bottom of the screen there is an error message. It says, relation product already exists. This means our product table already exists. But of course it exists. We expect it to exist if we are adding data to it. Why do we get this error? It's because when we click on the execute button, all of the statements on the screen are run. This means we click to execute, and the first statement that is run is the create table statement. We try to create a table that already exists, so we get this error. How can we fix this? One way is to delete the create table statement, but let's say we want to keep it there. Another way is to just run our insert statement by itself, and not the create table statement. To do this, highlight the insert statement, and click on the execute button again. This means only the insert statement is run. We can see a message at the bottom of the screen. It says, column James does not exist. It also shows the point in our statement that it refers to, which is the James inside the values part of the statement. What does this mean? James is not a column. It's a value we want to insert. Well, this error happens because the database thinks that James is a column, but we want to add a value of James to our product name column. The database thinks it's a column because we haven't said it is a specific value for our table. In SQL, whenever we specify a text value like this, we need to enclose it within single quotes. This will mean the database treats it like a text value, rather than thinking it's a column or something else. So, add a single quote before and after the James value here. You'll notice the value change color from black to brown or a dark orange color. This is good. It means that James is now treated as a text value. Do we need to do the same thing to the price value of 50? The short answer is no, we don't. Because SQL knows that numbers are not column names. So, let's highlight our insert statement again and run it. The message at the bottom of the screen should say insert 01 and query return successfully. We have successfully added a record of data to our table. We've added the record. How can we see it? We can write another type of SQL statement to see data, which is called a screen. Which is called a select statement, because it starts with the select keyword. This is probably the most common type of statement you'll write, but we'll start with a basic one here. Go to a new line and type the select keyword. After select, we need to specify what columns we want to see. You can specify all columns in the table by using the star character. There is a way to specify the names of the individual columns, but we'll cover that in the next lesson. So, after the star character, type the word from. We then need to specify the table where we want to see the data. In our example, we want to see data in the product table, so type in product. Add a semicolon and we are done with our query. Highlight the query and click execute. At the bottom of the screen, you should see a small table of results. You'll see the column headings here, product name and price, including their data types that you specified when you created the table. Product name is shown as character varying, because that's the data type specific to Postgres that is used when you use the VARCHAR data type. There is one record in the table, with a name of genes and a price of 50. Well done. You've successfully run a select statement on your table and seen the data in it. You may want to insert more than one row into your table. You can do this by writing another insert statement or making changes to the insert statement you have on your screen here. And running it. For example, we can change genes to address and change 50 to 100. We can highlight this statement and run it, and it should say it was successful. We don't need to keep the old statement here. The one that was for genes, for everything to work. Now highlight and run this select statement again. You should see the results at the bottom of the screen that include both the genes and dress products. We've covered quite a few of the basics of SQL in this lesson. You connected to the Postgres database, created a table, added some data to the table, and viewed this data. If you have any questions on anything we've covered in this video, let me know in the comments section. In the next video in this series, we'll learn more about selecting data from the table and making changes to the data that's already in the table. I recommend installing your Postgres database and following along by writing the SQL code in this video to get started with learning SQL. If you want to learn more about database design in SQL, visit my website at database.com. If you like this video, consider subscribing to my channel. Thanks for watching.