title: Columns Containing Sets Of Values
tags: postgres set

This is the `ARRAY` type, not a set. As SQL uses the `SET` keyword in `UPDATE`.

```sql
CREATE TABLE a ( id SERIAL PRIMARY KEY, name TEXT, s TEXT[] );
INSERT INTO a ( name, s ) VALUES ( 'Hello World', '{ "hello", "world" }' ), ( 'Mr Flibble', '{ "mr", "flibble" }' );
SELECT name, s FROM a WHERE 'hello' = ANY( s );
```
outputs
```
    name     |       s       
-------------+---------------
 Hello World | {hello,world}
```

This does not prevent duplicate elements in a column, e.g. `{ "hello", "hello" }` is possible.