MySQL: GROUP BY
HTML-код
- Опубликовано: 19 июн 2024
- #MySQL #tutorial #course
You can copy and paste all of the following statements if you would like to follow along in this video.
P.S. Make sure you have a customers table if you're linking the foreign key on customer_id.
------------------------------------------------------------
DROP TABLE IF EXISTS transactions;
CREATE TABLE transactions (
transaction_id INT PRIMARY KEY AUTO_INCREMENT,
amount DECIMAL(5, 2),
customer_id INT,
order_date DATE,
FOREIGN KEY (customer_id)
REFERENCES customers(customer_id)
);
INSERT INTO transactions
VALUES (1000, 4.99, 3, "2023-01-01"),
(1001, 2.89, 2, "2023-01-01"),
(1002, 3.38, 3, "2023-01-02"),
(1003, 4.99, 1, "2023-01-02"),
(1004, 1.00, NULL, "2023-01-03"),
(1005, 2.49, 4, "2023-01-03"),
(1006, 5.48, NULL, "2023-01-03");
SELECT * FROM transactions;
------------------------------------------------------------
00:00:00 intro
00:00:16 data for this demo
00:00:00 GROUP BY
00:03:19 HAVING
00:04:36 conclusion
You can copy and paste all of the following statements if you would like to follow along in this video.
P.S. Make sure you have a customers table if you're linking the foreign key on customer_id.
------------------------------------------------------------
DROP TABLE IF EXISTS transactions;
CREATE TABLE transactions (
transaction_id INT PRIMARY KEY AUTO_INCREMENT,
amount DECIMAL(5, 2),
customer_id INT,
order_date DATE,
FOREIGN KEY (customer_id)
REFERENCES customers(customer_id)
);
INSERT INTO transactions
VALUES (1000, 4.99, 3, "2023-01-01"),
(1001, 2.89, 2, "2023-01-01"),
(1002, 3.38, 3, "2023-01-02"),
(1003, 4.99, 1, "2023-01-02"),
(1004, 1.00, NULL, "2023-01-03"),
(1005, 2.49, 4, "2023-01-03"),
(1006, 5.48, NULL, "2023-01-03");
SELECT * FROM transactions;
------------------------------------------------------------
-- EXAMPLE 1 --
SELECT SUM(amount), order_date
FROM transactions
GROUP BY order_date;
-- EXAMPLE 2 --
SELECT COUNT(amount), customer_id
FROM transactions
GROUP BY customer_id
HAVING COUNT(amount) > 1 AND customer_id IS NOT NULL;
I've read the article about GROUP BY but still don't understand. Your explanation is simply the best!
I love your voice and the way that you teach us. Thank you Bro Code
bro you are a treasure , thank you for existing
Your videos have really helped me. I really appreciate it!
Thanks a lot for explaining it so nicely
Dude couldn’t have a better timing i just got my assignment in sql
FINALLY an explanation that i understand. Thanks!
Thank you, great explanation
life saver, I owe u my life
Love from TN too , India!
Thank you, it helped me a lot
thank you i have an asessment tomorrow it helped a lot
Thank you very much
THANK YOU 😭
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Well explained.
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Just like wowww
Thanks
what a top notch explanation sir.
u the goat
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Love you bro
we can use where Clause also.
Give the Where clause above the GroupBy Clause.But for Aggregate functions we need to use Having within Groupby
Love From Bangladesh 🇧🇩
Please make a bash & powershell series too 😊
Can you make a video, explaining the math or innerworkings of GROUP by? I think what others seemed to get confused about group by is the fact that the math isn't mathin'.
I mean that you visualize select, but it's hard to visualize into thinking the group by. :)
Questions like: is it correct that 2 invisible became a pattern marker for group by? Something like that! 😁
THANK YOU SO MUCH AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
Are you able to do more videos about javaFX?
I like your voice bro *_^
Hey I am also using MySQL workbench mine text editor is not same as you how I can changed it to dark and like you
Can we use DISTINCT instead of GROUP BY
𝓅𝓇𝑜𝓂𝑜𝓈𝓂
Would you marry me?
could you please share the sql dump so we could also practice with the exact data you have?