CS50 SQL - Lecture 1 - Relating

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  • เผยแพร่เมื่อ 4 ธ.ค. 2024

ความคิดเห็น • 48

  • @mahmudhasanrimel9347
    @mahmudhasanrimel9347 ปีที่แล้ว +100

    Even though I have intermediate knowledge of SQL, I am taking this course to refresh myself. The explanations are crystal clear, and the topics are well-organized. Overall, I would give this course a 5-star rating.

  • @GenZ_01_
    @GenZ_01_ 3 หลายเดือนก่อน +10

    Cs50 courses are on another league .
    Carter you’re a great teacher.
    Thank you all🙏🏽

  • @janetkalu3064
    @janetkalu3064 ปีที่แล้ว +12

    Thank you for putting this course out for us. I can proudly say that I have never enjoyed querying tables until now. You make it seamless and stuck in my head. I don't have to repeatedly memorize queries, without understanding the underlying concepts. Thank you so much

  • @ManhTienNguyen-q5e
    @ManhTienNguyen-q5e ปีที่แล้ว +21

    Thank you so much for putting this online and free for us. I'm learning Data Science and getting started with SQL is really easier with your instruction.

  • @WarbossPepe
    @WarbossPepe ปีที่แล้ว +12

    You're a great teacher and communicator Carter. Thank you for doing what you do

  • @srisaisubramanyamdavanam9912
    @srisaisubramanyamdavanam9912 3 หลายเดือนก่อน +1

    Im grateful for taking this course to learn sql

  • @kamalkishor3127
    @kamalkishor3127 ปีที่แล้ว +6

    Great teacher, Awesome way of communication, each concept is crystal clear and easy to understand.
    Love to see more videos from you.
    Great thing CS50.
    💌

  • @alainrouleau
    @alainrouleau 7 หลายเดือนก่อน +1

    Thanks so much!
    I finally understand, after all these years, how JOIN actually works and all its variants. Love the animated joins. Very nice to see what happens visually. That helped to explain things quite a lot.
    The query within a query, aka as subqueries or nested queries, was all very interesting as well. Didn't realize you could go so deep and do something like that. You know, multiple nested queries all on one line. Pretty crazy.

  • @msantosuk
    @msantosuk 3 หลายเดือนก่อน +1

    Great course, I'm learning so much. Congratulations guys! Carter is a great teacher.

  • @SamraatMaharjan
    @SamraatMaharjan 7 หลายเดือนก่อน

    I am absolutely loving these playlists.

  • @IbrokhimjonMakhammadjonov
    @IbrokhimjonMakhammadjonov 18 วันที่ผ่านมา

    great explanation, much thanks for you

  • @ThatsPety
    @ThatsPety 21 วันที่ผ่านมา

    2:43 Small correction: they are not called relational databases because tables have relationships between them. Extremely common misconception. They are called relational databases because how they work is based on something called "relational algebra"

  • @MOHAMEDTAHARFERHAT
    @MOHAMEDTAHARFERHAT 8 หลายเดือนก่อน

    Great explaination and so unique way of teaching it help me so much in university 🥰

  • @swampguy277
    @swampguy277 4 หลายเดือนก่อน

    This guy talks as well as Malan, very good course

  • @SothearithKONGMrMuyKhmer
    @SothearithKONGMrMuyKhmer 8 หลายเดือนก่อน +1

    Great! Thanks a lot for this tutorial! 🥰

  • @ramankr0022
    @ramankr0022 9 หลายเดือนก่อน +1

    Thank you!

  • @mehmedkukavica8076
    @mehmedkukavica8076 10 หลายเดือนก่อน +1

    Super

  • @not_amanullah
    @not_amanullah 8 หลายเดือนก่อน

    thanks ❤

  • @RvyvjjRejauvy
    @RvyvjjRejauvy 10 หลายเดือนก่อน

    In moneyball ERD have two tables players and salaries. relation between table players and table salaries 1.N but some players LIKE Satchel Paige doesnt have matches, i dont get something or its mistake

  • @rebekahmenn2118
    @rebekahmenn2118 ปีที่แล้ว +1

    Can anyone figure out why my query is coming back as incorrect? The prompt for Lesson 1, Question 12 in the DESE set of questions is:
    "Write a SQL query to find public school districts with above-average per-pupil expenditures and an above-average percentage of teachers rated “exemplary”. Your query should return the districts’ names, along with their per-pupil expenditures and percentage of teachers rated exemplary. Sort the results first by the percentage of teachers rated exemplary (high to low), then by the per-pupil expenditure (high to low)."
    And here's my query:
    SELECT "districts"."name", "staff_evaluations"."exemplary", "expenditures"."per_pupil_expenditure" FROM "districts"
    JOIN "expenditures" ON "expenditures"."district_id" = "districts"."id"
    JOIN "staff_evaluations" ON "staff_evaluations"."district_id" = "districts"."id"
    WHERE "staff_evaluations"."exemplary" > (
    SELECT AVG("staff_evaluations"."exemplary")
    FROM "staff_evaluations"
    ) AND "expenditures"."per_pupil_expenditure" > (
    SELECT AVG("expenditures"."per_pupil_expenditure")
    FROM "expenditures"
    )
    ORDER BY "staff_evaluations"."exemplary" DESC, "expenditures"."per_pupil_expenditure" DESC;
    Every time I check my answers, CS50 tells me this is wrong but I can't figure out why.

  • @tiwoni972mad
    @tiwoni972mad ปีที่แล้ว +2

    WEELL WE'RE BBBACK!!!!

  • @shauryathakkar2274
    @shauryathakkar2274 8 หลายเดือนก่อน

    Why would we use subqueries if we can use joins instead ???

    • @Charky32
      @Charky32 6 หลายเดือนก่อน +2

      There's no need to Join, a subquery will sack for exactly what data we want Join will search the joined table and which multiple conditions which is inefficient

  • @mastertoru5531
    @mastertoru5531 ปีที่แล้ว

    Is there any reason why at 1:09:42 , "NULL" did not appear for the presenter?

    • @AryanShetty-z3z
      @AryanShetty-z3z ปีที่แล้ว

      Bro how can I download software he is using.

    • @ericvaish
      @ericvaish ปีที่แล้ว

      @@AryanShetty-z3z VS Code

    • @ericvaish
      @ericvaish ปีที่แล้ว

      @mastertoru5531 It is the property of SQLite to not show NULL. Different RDBMS follow different convention.

  • @HasiburRahman-e6r
    @HasiburRahman-e6r 8 หลายเดือนก่อน

    Where can I find the data file?

  • @joaopauloduarteferreira9797
    @joaopauloduarteferreira9797 4 หลายเดือนก่อน

    Where do I take this data bases used in the course?

    • @andresnunez5625
      @andresnunez5625 3 หลายเดือนก่อน

      Hi! there are a link named "set of problem" in each week class when you register in the course in the edx harvardX page

  • @MehmetAliTukenmez
    @MehmetAliTukenmez ปีที่แล้ว +2

    Do you have the solutions for the problem set?

    • @cherishkansara7851
      @cherishkansara7851 ปีที่แล้ว +1

      We could help eachother in doing problem sets if you want

    • @andresnunez5625
      @andresnunez5625 3 หลายเดือนก่อน

      Hi!, I would like to know if you made a group to help each other with the problem set

  • @tshepomalalane4140
    @tshepomalalane4140 4 หลายเดือนก่อน

    Nested querying feels like recursion somehow...

    • @SingularityHRT
      @SingularityHRT หลายเดือนก่อน +1

      It is not anywhere close. Nested querying is like using a function inside another function. That's it. Recursion is calling the same function inside that very function.

  • @mdryan8
    @mdryan8 7 หลายเดือนก่อน

  • @AryanShetty-z3z
    @AryanShetty-z3z ปีที่แล้ว +2

    Guys how can i download the software or sqlite shown in this image begginer i wanted to code along with him; your help would be appreciated ❤

  • @mukhtarabdi824
    @mukhtarabdi824 ปีที่แล้ว +1

    When the problmes will be released?

    • @aamirshekh934
      @aamirshekh934 ปีที่แล้ว +6

      They are out on the edx platform.

  • @Amoz21
    @Amoz21 6 หลายเดือนก่อน +2

    Say no to struggling with sql

  • @kursataydn571
    @kursataydn571 ปีที่แล้ว

    I cant see tables in my longlist when i enter ".tables "it just outputs longlist any solution for that? Thanks!

    • @ericvaish
      @ericvaish ปีที่แล้ว

      Make sure you downloaded the file longlist-2.db

    • @mateuszmarchewka6127
      @mateuszmarchewka6127 ปีที่แล้ว +1

      @@ericvaish where do we download this file from?

  • @DM-ul5yc
    @DM-ul5yc 4 หลายเดือนก่อน

    He refers to a woman as they. So progressive of him.

  • @SrijanPaulsatya
    @SrijanPaulsatya 3 หลายเดือนก่อน

    bro just did space, space, space, space ☠

  • @immotile
    @immotile 6 หลายเดือนก่อน +2

    What's going on with Carter? Compared to the first SQL lesson he's like on speed!
    @davidjmalan what have you done with him? :)