47 lines
2.3 KiB
Markdown
47 lines
2.3 KiB
Markdown
---
|
|
title: SQL Group By Statement
|
|
---
|
|
|
|
## SQL Group By Statemet
|
|
|
|
### Example of use
|
|
GROUP BY gives us a way to combine rows and aggregate data.
|
|
|
|
The data used is from the campaign contributions data we've been using in some of these guides.
|
|
|
|
The following SQL statement is answering the question: "which candidates received the largest total contributions in 2016 BUT only those that had more than $20 Million USD?"
|
|
|
|
Ordering this data set in a descending (DESC) order places the candidates with the largest total contributions at the top of the list.
|
|
|
|
```sql
|
|
SELECT Candidate, Election_year, sum(Total_$), count(*)
|
|
FROM combined_party_data
|
|
WHERE Election_year = 2016
|
|
GROUP BY Candidate, Election_year -- this tells the DBMS to summarize by these two columns
|
|
HAVING sum(Total_$) > 20000000 -- limits the rows presented from the summary of money ($20 Million USD)
|
|
ORDER BY sum(Total_$) DESC; -- orders the presented rows with the largest ones first.
|
|
```
|
|
|
|
```text
|
|
+--------------------------------------------------+---------------+-------------------+----------+
|
|
| Candidate | Election_year | sum(Total_$) | count(*) |
|
|
+--------------------------------------------------+---------------+-------------------+----------+
|
|
| CLINTON, HILLARY RODHAM & KAINE, TIMOTHY M (TIM) | 2016 | 568135094.4400003 | 126 |
|
|
| TRUMP, DONALD J & PENCE, MICHAEL R (MIKE) | 2016 | 366853142.7899999 | 114 |
|
|
| SANDERS, BERNARD (BERNIE) | 2016 | 258562022.17 | 122 |
|
|
| CRUZ, RAFAEL EDWARD (TED) | 2016 | 93430700.29000005 | 104 |
|
|
| CARSON, BENJAMIN S (BEN) | 2016 | 62202411.12999996 | 93 |
|
|
| RUBIO, MARCO ANTONIO | 2016 | 44384313.9 | 106 |
|
|
| BUSH, JOHN ELLIS (JEB) | 2016 | 34606731.78 | 97 |
|
|
+--------------------------------------------------+---------------+-------------------+----------+
|
|
7 rows in set (0.01 sec)
|
|
```
|
|
|
|
|
|
As with all of these SQL things there is MUCH MORE to them than what's in this introductory guide.
|
|
|
|
I hope this at least gives you enough to get started.
|
|
|
|
Please see the manual for your database manager and have fun trying different options yourself.
|
|
|