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# postgres add object to jsonb array from the same column

We want to create a new column where it's a combination for several column as a jsonb object.

```sql
ALTER TABLE items
	ADD new_arrays_col jsonb DEFAULT '[]';

UPDATE items i1
SET new_arrays_col = new_arrays_col || JSON_BUILD_OBJECT(
		'col1', col1,
		'col1', col2
	)::jsonb
```

the `new_arrays || ...` is kind of like appending to exisitng array with an object. `JSON_BUILD_OBJECT` is a postgres function to create a JSON object from the parameters