I have a table with Parent-Child Relation in the same Table. Some Sample Data
id │ name │ parent │ is_active
════╪══════════════════════╪════════╪═══════════
1 │ Company A │ null │ true
2 │ Child of A │ 1 │ true
3 │ 2Child of A │ 1 │ true
4 │ 3Child of A │ 1 │ true
5 │ 0 Single Company │ null │ true
6 │ 1 Single Company │ null │ true
7 │ 2 Single Company │ null │ true
8 │ Parent Company B │ null │ true
9 │ 0 Child Company of B │ 8 │ true
10 │ 1 Child Company of B │ 8 │ true
11 │ 2 Child Company of B │ 8 │ true
12 │ 3 Child Company of B │ 8 │ true
I want to write two queries
get all the parent records (only parent records) Example: id 1,8
Get all the single records (only records does not come under parent-child) Example: 5,6,7
Please help to write select queries.