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https://github.com/fortunewalla/birdstrikes

birdstrikes database created for postgresql with simple sample queries
https://github.com/fortunewalla/birdstrikes

birdstrikes csv data-analysis data-science database dataset pgsql postgresql practice sample sql sql-query workshop

Last synced: 4 months ago
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birdstrikes database created for postgresql with simple sample queries

Host: GitHub
URL: https://github.com/fortunewalla/birdstrikes
Owner: fortunewalla
Fork: true (zoltanctoth/smalldata-training)
Created: 2023-08-01T05:08:07.000Z (over 1 year ago)
Default Branch: master
Last Pushed: 2023-08-01T07:29:03.000Z (over 1 year ago)
Last Synced: 2024-09-19T14:07:33.496Z (4 months ago)
Topics: birdstrikes, csv, data-analysis, data-science, database, dataset, pgsql, postgresql, practice, sample, sql, sql-query, workshop
Homepage:
Size: 2.21 MB
Stars: 0
Watchers: 0
Forks: 0
Open Issues: 0
Metadata Files:
- Readme: README.md

Awesome Lists containing this project

README

        # smalldata-training

## Selecting data

Select all data

`SELECT * FROM birdstrikes;`

Select all & limit

`SELECT * FROM birdstrikes LIMIT 10;`

Select certain fields

`SELECT bird_size, cost FROM birdstrikes LIMIT 10;`

## Ordering data

Order by a field

`SELECT state, cost FROM birdstrikes ORDER BY cost LIMIT 10;`

Order by a multiple fields

`SELECT state, cost FROM birdstrikes ORDER BY state, cost LIMIT 10;`

Order by a multiple fields

`SELECT state, cost FROM birdstrikes ORDER BY state, cost LIMIT 10;`

Reverse ordering

`SELECT state, cost FROM birdstrikes ORDER BY cost DESC;`

Reverse ordering by multple fields

`SELECT state, cost FROM birdstrikes ORDER BY state DESC, cost;`

## Renaming fields

`SELECT bird_size as size, state FROM birdstrikes;`

```

SELECT

    state || ' - ' || flight_date as title,

    cost

FROM birdstrikes

ORDER BY cost DESC;

```

## Filtering data

Filter by field value

`SELECT * FROM birdstrikes WHERE state = 'Alabama';`

Filter by multiple conditions

`SELECT * FROM birdstrikes WHERE state = 'Alabama' AND bird_size = 'Small';`

`SELECT * FROM birdstrikes WHERE state = 'Alabama' OR state = 'Missouri';`

`SELECT * FROM birdstrikes WHERE state IN ('Alabama', 'Missouri');`

String operations:

`SELECT state FROM birdstrikes WHERE state LIKE 'A%' OR state LIKE '%a';`

`SELECT state FROM birdstrikes WHERE LOWER(state) = 'alabama';`

Lowercase: `LOWER`

Uppercase: `UPPER`

```

SELECT EXTRACT(DOW FROM flight_date) as day_of_week, * FROM birdstrikes;

```

It can go complicated:

```

SELECT state, cost, bird_size FROM birdstrikes

WHERE (LOWER(state) = 'alabama'

        OR LOWER(state) = 'missoury')

      AND (bird_size = 'Small')

ORDER BY cost DESC;

```

## Removing duplicates

`SELECT DISTINCT state, size FROM birdstrikes;`

## WORKSHOP

* Hány dollár volt a legtöbb kár?

* ^Ez melyik államban történt és milyen madár okozta?

* Melyik az első három állam ABC sorrendben?

* Milyen méretű madarak vannak az adatbázisban?

* Mekkora méretű madár okozta a legnagyobb kárt Missouri-ban?

* Hány államban történt baleset?

* A hét melyik napján történt a legnagyobb kár?

* How many dollars was the most damage?

* ^In what state did this happen and what kind of bird caused it?

* Which are the first three states in ABC order?

* What size birds are in the database?

* What size bird caused the most damage in Missouri?

* In how many states did the accident occur?

* On which day of the week did the greatest damage occur?

* What's the maximum overall cost

* ^^ In which state did this accident happen?

* Display the first three states in alphabetical order?

* Display the bird sizes (don't display the "empty" cell)

* What is the size of the bird that caused the biggest damage in Missouri?

## SOME more DML

Updating

```

UPDATE birdstrikes SET aircraft='Unknown' WHERE aircraft IS NULL;

```

Deleting

```

DELETE FROM birdstrikes WHERE aircraft = 'Unknown';

```

Truncating

```

TRUNCATE birdstrikes;

```

## Groupping and aggregation

COUNT(*)

```

SELECT COUNT(*) FROM birdstrikes;

```

Simple aggregations

```

SELECT MAX(cost) FROM birdstrikes;

```

```

SELECT state, MAX(cost) AS max_cost FROM birdstrikes GROUP BY state ORDER BY state;

```

Multiple aggregate functions:

```

SELECT state, aircraft, COUNT(*), MAX(cost), MIN(cost), AVG(cost) FROM birdstrikes WHERE state LIKE 'A%' GROUP BY state, aircraft ORDER BY state, aircraft;

```

**Sometimes it doesn't work**:

```

SELECT aircraft, state, MAX(cost) AS max_cost FROM birdstrikes GROUP BY state ORDER BY state;

```

Let's fix it:

```

SELECT state, aircraft, MAX(cost) AS max_cost FROM birdstrikes GROUP BY state, aircraft ORDER BY state, aircraft;

```

You can filter here, too:

```

SELECT state, aircraft, MAX(cost) AS max_cost FROM birdstrikes WHERE state LIKE 'A%' GROUP BY state, aircraft ORDER BY state, aircraft;

```

Advanced groupping - HAVING

```

SELECT state, COUNT(*) FROM birdstrikes GROUP BY state HAVING COUNT(*) > 100;

```

```

SELECT state, COUNT(*) FROM birdstrikes

WHERE state IS NOT NULL

GROUP BY state HAVING COUNT(*) > 100;

```

## WORKSHOP

 * Mégegyszer: Hány államban történt baleset? (Most egy szám legyen a képernyőn az eredmény)

 * Melyik államban történt a legtöbb összkár

 * Átlagosan melyik méretű madár mekkora kárt okoz?

 * Írasd ki madár és állam-méretenként (tehát 2 mezőn együttesen csoportosítva) a legnagyobb kár értékét.

 * ^^ Ebből irasd ki az átlagos kárt azokban az állam/méret csoportokban, ahol több, mint 1000 baleset történt

* Again: In how many states did the accident occur? (Now the result should be a number on the screen)

* In which state did the most total damage occur?

* On average, what size bird does how much damage?

* Write out the value of the largest damage per bird and state size (ie grouped together in 2 fields).

* ^^ From this, write down the average damage in the states/size groups where more than 1000 accidents occurred

 * Which is the state with the most accidents?

 * List the average (AVG) damage caused by each bird size?

 * List the maximum (MAX) damage caused by each bird size in each state.

 * ^^ Only show those rows from the above solutions which have a bigger damage than $100000

## JOINING

```

SELECT * FROM emberek

JOIN varosok ON (emberek.varos_id = varosok.id);

```

```

SELECT * FROM emberek

INNER JOIN varosok ON (emberek.varos_id = varosok.id);

```

```

SELECT * FROM emberek

LEFT JOIN varosok ON (emberek.varos_id = varosok.id);

```

```

SELECT * FROM emberek

RIGHT JOIN varosok ON (emberek.varos_id = varosok.id);

```

```

SELECT * FROM emberek

FULL OUTER JOIN varosok ON (emberek.varos_id = varosok.id);

```

## Create table as SELECT

```

CREATE TABLE birdstrikes_denorm AS

    SELECT b.*,s.id as state_id

    FROM birdstrikes b

       LEFT JOIN states s ON (b.state = s.state_name);

ALTER TABLE birdstrikes_denorm DROP state;

```

## WORKSHOP

 * Újra: Hány államban történtek balesetek?

 * Nézd meg, hogy hány sort látunk a különböző joinoknál a táblában (INNER, LEFT, RIGHT, FULL OUTER)

 

* Again: In how many states were there accidents?

* See how many rows we see for the different joins in the table (INNER, LEFT, RIGHT, FULL OUTER)

### Using Zeppelin Notebook

```

%psql.sql SELECT EXTRACT(dow FROM flight_date) as week, COUNT(*) FROM birdstrikes GROUP BY week;

```

```

%psql.sql %psql.sql SELECT bird_size, damage, count(*) FROM birdstrikes WHERE bird_size IS NOT NULL and damage IS NOT NULL GROUP BY bird_size, damage;

```