SQL Joins: A Guide and Examples

📝 Get my free SQL Cheat Sheets: www.databasestar.com/get-sql-...
🎓 Learn and become confident in SQL: databasestar.mykajabi.com/sql...
SQL joins are a commonly used feature when writing queries. They let you combine two (or more) tables together in your SQL query and see a single set of results.
In this video, you'll learn a bit more about what SQL joins are, why they are needed, the different types of joins, and examples of each in a SELECT query.
I'll also share a few tips on working with joins and things to avoid.
Related videos:
How to Join 3 Tables: • SQL Join 3 Tables: How...
Self Joins: • Self Join in SQL
Timestamps:
00:00 Start
00:16 What is a join?
00:48 Sample tables
01:38 Start of query
01:58 Inner Join
04:49 Left Outer Join
06:10 Right Outer Join
07:10 Full Outer Join
07:38 Joins are not bad
08:16 Using keyword
08:46 Natural Join
09:17 Joins in a Where clause

[@anjumshaikh7735]

I just love the way you break down the hardest topics & concepts so clear , easy to understand with simple examples . Thank you so much. ❤❤❤❤

[@DatabaseStar]

Thanks! I’m glad you enjoyed the video and we’re able to understand the concepts from it.

[@obscuredbyclouds1209]

Extra thanks for the subtitles! Even if I don't have a listening issue, they help understanding better

[@DatabaseStar]

Thanks! Glad to hear they are helpful for you.

[@sambarjunk]

Clear and to the point

[@DatabaseStar]

Thanks!

[@ladyzavi]

This video was so helpful. Thank you!

[@DatabaseStar]

Glad it was helpful!

[@RainNColer]

Damn im learning selftaught full stack development and already learned MERN stack but felt the need to learn SQL, and im loving it, this channel is so crystal clear with all the topics that i encounter when practicing with my project and want to learn. A great thing about SQL is that is an ancient concept and will prevail even longer so all this information will be valuable for years to come :)

[@DatabaseStar]

Thanks for the kind words, and I'm glad to hear my videos are helpful. Yeah, SQL has been around for a while and the fundamentals don't change.

[@surajpatil3579]

Thanks keep making content like this

[@DatabaseStar]

Will do! Glad you like it.

[@sabuein]

Thank you.

[@DatabaseStar]

You're welcome!

[@milabibik9318]

Thanks!

[@DatabaseStar]

No problem!

[@basilisk9864]

helpful, keep it up

[@DatabaseStar]

Thanks, will do!

[@thanzeeljalaldeen]

can we do joins without foreignkey?

[@DatabaseStar]

Yes, you can. As long as the fields in both tables represent the same thing, you can do a join and there does not have to be a foreign key created.

[@RDL-yw5wy]

Thank you
sorry I didn't find a link of the video that contains join three tables or more

[@DatabaseStar]

No problem, the link is here: ua-cam.com/video/TGt2xa7EzvI/v-deo.html

[@himanshuchhikara4918]

super awesome

[@DatabaseStar]

Thanks!

[@spyrex3988]

can we really join without foreign key -- primary key relation?

[@DatabaseStar]

Yeah, you can. You would usually join between PK and FK, but you don't need to have those constraints to make the join work. If both columns represent the same thing then you can join.
You can actually join on two columns that have two different sets of data, but your results will not be meaningul.

[@parko1965]

So correct me if I'm wrong these two tables break referential integrity rules, but joins still possible?

[@DatabaseStar]

What about these tables breaks referential integrity rules? In general, you can still join tables if they break rules like that, as long as the data being joined is the same (e.g. both IDs or names or values represent the same thing)

[@parko1965]

@@DatabaseStar So I can create a record in a child table not related to to a parent table record.

[@DatabaseStar]

Yes, that's right, you can. If you leave the foreign key empty the row will still be inserted. You could put a Not Null constraint on it to prevent that though.