48 lines
2.5 KiB
Markdown
48 lines
2.5 KiB
Markdown
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---
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title: SQL Having Clause
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---
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## SQL Having Clause
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HAVING gives the DBA or SQL-using programmer a way to filter the data aggregated by the GROUP BY clause so that the user gets a limited set of records to view.
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### Example of use
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The HAVING clause is like the WHERE clause, exept it acts on the grouped data. In this case, the user will only see the largest amounts.
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This data is from the campaign contributions data we've been using in some of these guides.
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This SQL statement is answering the question: "which candidates received the largest total contributions in 2016 BUT only those that had more than 8$20 Million USD?"
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Ordering this data set in a descending (DESC) order places the candidates with the largest total contributions at the top of the list.
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```sql
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SELECT Candidate, Election_year, sum(Total_$), count(*)
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FROM combined_party_data
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WHERE Election_year = 2016
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GROUP BY Candidate, Election_year -- this tells the DBMS to summarize by these two columns
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HAVING sum(Total_$) > 20000000 -- limits the rows presented from the summary of money ($20 Million USD)
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ORDER BY sum(Total_$) DESC; -- orders the presented rows with the largest ones first.
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```
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```text
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+--------------------------------------------------+---------------+-------------------+----------+
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| Candidate | Election_year | sum(Total_$) | count(*) |
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+--------------------------------------------------+---------------+-------------------+----------+
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| CLINTON, HILLARY RODHAM & KAINE, TIMOTHY M (TIM) | 2016 | 568135094.4400003 | 126 |
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| TRUMP, DONALD J & PENCE, MICHAEL R (MIKE) | 2016 | 366853142.7899999 | 114 |
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| SANDERS, BERNARD (BERNIE) | 2016 | 258562022.17 | 122 |
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| CRUZ, RAFAEL EDWARD (TED) | 2016 | 93430700.29000005 | 104 |
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| CARSON, BENJAMIN S (BEN) | 2016 | 62202411.12999996 | 93 |
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| RUBIO, MARCO ANTONIO | 2016 | 44384313.9 | 106 |
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| BUSH, JOHN ELLIS (JEB) | 2016 | 34606731.78 | 97 |
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+--------------------------------------------------+---------------+-------------------+----------+
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7 rows in set (0.01 sec)
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```
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As with all of these SQL things there is MUCH MORE to them than what's in this introductory guide.
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I hope this at least gives you enough to get started.
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Please see the manual for your database manager and have fun trying different options yourself.
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