Aliases

Quick reference

• 00:05 In this video, I wanna talk about aliases, and aliases are used to temporarily rename
• 00:10 columns and tables too for that matter but we're gonna look at columns in this video.
• 00:14 So we can look at our column, and our column names are first name, last name,
• 00:18 email address, phone number, age, city, and country.
• 00:21 Well, whenever we're displaying data,
• 00:23 we may want to label them as different things.
• 00:26 Instead of city, we might want to label it as current city or whatever.
• 00:29 So alias is good for that.
• 00:31 Now, in the next few videos we're gonna be talking about using multiple tables and
• 00:35 pulling data from two or more tables and smushing them together.
• 00:39 When that happens,
• 00:39 we might want to label them differently than they're currently labeled.
• 00:42 So we'll use aliases for that, and aliases are pretty simple.
• 00:45 We just type in the column name we wanna mess with, and let's do City.
• 00:51 City. And then we just type A-S, AS, and
• 00:54 then just give it whatever you want to call it.
• 00:58 So, Current City let's change it to.
• 01:02 So if we run this query, boom.
• 01:04 We see Current City here at the top.
• 01:07 Now, if we get rid of the alias and run it again, you see it's just city.
• 01:11 If we wanna change it, Current City.
• 01:14 Now, if we get rid of all of this and just go back to our regular wild card
• 01:19 thing there, we can see the city hasn't changed.
• 01:21 The actual name of the column hasn't changed.
• 01:24 Like I said, this is just temporary.
• 01:25 It's just for the duration of that specific query that you can do that.
• 01:29 So that's aliases, very useful.
• 01:31 Now, like a lot of things in SQL, you can string these things together.
• 01:35 So let's go first
• 01:39 name and last name.
• 01:45 And let's run this query.
• 01:46 So we have a column for first name and a column of last name.
• 01:49 What if we want to put these two together?
• 01:51 Well, we're gonna look through this pass, but we can do this addition thing.
• 01:55 And let's give it an alias.
• 01:57 Let's call it As Customer Name.
• 02:02 Boom, now they get smushed into one column and the column is labeled Customer Name.
• 02:07 Now you'll notice the two words, the first name and
• 02:10 the last name, are smushed together and there's no space in between.
• 02:13 You can actually add a space just by doing that.
• 02:17 So we're just adding a single quotation mark with a space.
• 02:19 I just put a space in there.
• 02:21 If we execute that, boom, John Elder.
• 02:23 So very, very cool.
• 02:25 And it's not just stringing together things like this.
• 02:28 You can also put multiple ones on each line.
• 02:30 So we can give this a comma and then we can pull in our city like we did earlier
• 02:35 and give that an alias as we actually, whoops, we don't need those,
• 02:40 we need quotation marks.
• 02:41 Let's call it, what did we call it, Current City before?
• 02:44 So if execute that, boom, we get two columns, Current Customer and
• 02:47 Current City.
• 02:48 And both of the headers, the column names, have been given the alias that we want.
• 02:53 And like I said, if we get rid of all of this, go back to our wildcard,
• 02:57 the column names don't change.
• 02:59 They're physically not being changed.
• 03:01 We're just giving them a temporary alias.
• 03:03 For the duration of that query.
• 03:04 So those are aliases.
• 03:06 Pretty cool, very useful.
• 03:07 In the next video we're gonna look at inner join.

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