PostgreSQL Group By
The PostgreSQL GROUP BY is used when at least one of the aggregation functions(count, max, min, sum, avg) is used in a select.
Group By syntax
SELECT column_name1, column_name2, function(column_name1)
FROM table_name
GROUP BY column_name1, column_name2
Group By example
Goods table
| id | good_type | name | description | price |
|---|
| 1 | A | Car_1 | Car 1 description | 100 |
| 2 | A | Car_2 | Car 2 description | 200 |
| 3 | A | Car_3 | Car 3 description | 100 |
| 4 | B | Boat_4 | Boat 4 description | 500 |
| 5 | B | Boat_5 | Boat 5 description | 300 |
| 6 | C | Train_1 | Train 123 description | 800 |
SELECT good_type, count(good_type) g_count
FROM goods
GROUP BY good_type
Result