The present invent
Introduction {#s1}
The present invent
A lot of people ar
Q: What is the di
Introduction {#Sec
This application c
For every $1,000
Q: How to fix "A
In case you missed

The Evolution of
The present invent
Q: Find the numbe
In this study, we
Q: SQL Server Man
# -*- encoding: ut
Beta-cell autoimmu
Q: Unable to pass
Q: How to set up
--- title: Gatsby
<<      >>
Q: PHP - How to sort list of items by id and date? For example I have an items item_id | category | order --------+----------+-------- 1 | red | NULL 2 | red | NULL 3 | blue | NULL 4 | blue | NULL 5 | red | NULL 6 | red | NULL 7 | blue | NULL 8 | blue | NULL 9 | red | NULL 10 | red | NULL 11 | blue | NULL 12 | blue | NULL 13 | red | NULL 14 | red | NULL 15 | red | NULL 16 | blue | NULL 17 | blue | NULL 18 | red | NULL 19 | red | NULL 20 | blue | NULL 21 | blue | NULL 22 | blue | NULL 23 | blue | NULL My expected result is item_id | category | order --------+----------+-------- 2 | red | NULL 3 | blue | NULL 6 | red | NULL 8 | blue | NULL 18 | red | NULL 19 | red | NULL 20 | blue | NULL 5 | red | NULL 7 | blue | NULL 15 | red | NULL 16 | blue | NULL 23 | blue | NULL 1 | red | NULL 4 | blue | NULL 10 | red | NULL 12 | blue | NULL 14 | red | NULL 22 | blue | NULL 21 | blue | NULL 14 | red | NULL 10 | red | NULL 1 | red | NULL 3 | blue | NULL 16 | blue | NULL 23 | blue | NULL 11 | blue | NULL 2 | red | NULL 7 | blue | NULL 20 | blue | NULL 5 | red | NULL 3 | blue | NULL 18 | red | NULL 21 | blue | NULL 6 | red | NULL 16 | blue | NULL 14 | red | NULL 4 | blue | NULL 19 | red | NULL 7 | blue | NULL 22 | blue | NULL 8 | blue | NULL 1 | red | NULL 5 | red | NULL 10 | red | NULL 11 | blue | NULL 16 | blue | NULL 1 | red | NULL 18 | red | NULL 11 | blue | NULL 8 | blue | NULL 20 | blue | NULL 14 | red | NULL 6 | red | NULL 3 | blue | NULL 21 | blue | NULL 7 | blue | NULL 22 | blue | NULL 18 | red | NULL 4 | blue | NULL 16 | blue | NULL 19 | red | NULL 5 | red | NULL 11 | blue | NULL 22 | blue | NULL 10 | red | NULL 7 | blue | NULL 21 | blue | NULL 23 | blue | NULL 18 | red | NULL 16 | blue | NULL 10 | red | NULL 22 | blue | NULL 11 | blue | NULL 7 | blue | NULL 10 | red | NULL 1 | red | NULL 18 | red | NULL 23 | blue | NULL 3 | blue | NULL 11 | blue | NULL 23 | blue | NULL 16 | blue | NULL 1 | red | NULL 7 | blue | NULL 2 | red | NULL 3 | blue | NULL 10 | red | NULL 4 | blue | NULL 19 | red | NULL 5 | red | NULL 18 | red | NULL 1 | red | NULL 23 | blue | NULL 22 | blue | NULL 16 | blue | NULL 10 | red | NULL 7 | blue | NULL 5 | red | NULL 18 | red | NULL 11 | blue | NULL 22 | blue | NULL 4 | blue | NULL 19 | red | NULL 3 | blue | NULL 16 | blue | NULL 18 | red | NULL 11 | blue | NULL 22 | blue | NULL 6 | red | NULL 1 | red | NULL 23 | blue | NULL 16 | blue | NULL 19 | red | NULL 7 | blue | NULL 2 | red | NULL 22 | blue | NULL 3 | blue | NULL 10 | red | NULL 4 | blue | NULL 5 | red | NULL 11 | blue | NULL 23 | blue | NULL 16 | blue | NULL 1 | red | NULL 22 | blue | NULL 7 | blue | NULL 2 | red | NULL 16 | blue | NULL 18 | red | NULL 11 | blue | NULL 22 | blue | NULL 4 | blue | NULL 7 | blue | NULL 10 | red | NULL 1 | red | NULL 23 | blue | NULL 3 | blue | NULL 11 | blue | NULL 23 | blue | NULL 18 | red | NULL 16 | blue | NULL 10 | red | NULL 22 | blue | NULL 11 | blue | NULL 6 | red | NULL 1 | red | NULL 23 | blue | NULL 16 | blue | NULL 19 | red | NULL 7 | blue | NULL 2 | red | NULL 22 | blue | NULL 3 | blue | NULL 10 | red | NULL 4 | blue | NULL 5 | red | NULL 11 | blue | NULL 23 | blue | NULL 18 | red | NULL 16 | blue | NULL 10 | red | NULL 22 | blue | NULL 11 | blue | NULL 7 | blue | NULL 10 | red | NULL 1 | red | NULL 23 | blue | NULL 3 | blue | NULL 11 | blue | NULL 23 | blue | NULL 18 | red | NULL 16 | blue | NULL 10 | red | NULL 22 | blue | NULL 11 | blue | NULL 6 | red | NULL 1 | red | NULL 23 | blue | NULL 16 | blue | NULL 19 | red | NULL 7 | blue | NULL 2 | red | NULL 22 | blue | NULL 3 | blue | NULL 10 | red | NULL 4 | blue | NULL 5 | red | NULL 11 | blue | NULL 23 | blue | NULL 18 | red | NULL 16 | blue | NULL 10 | red | NULL 22 | blue | NULL 11 | blue | NULL 7 | blue | NULL 10 | red | NULL 1 | red | NULL 23 | blue | NULL 3 | blue | NULL 11 | blue | NULL 23 | blue | NULL 18 | red | NULL 16 | blue | NULL 10 | red | NULL 22 | blue | NULL 11 | blue | NULL 6 | red | NULL 1 | red | NULL 23 | blue | NULL 16 | blue | NULL 19 | red | NULL 7 | blue | NULL 2 | red | NULL 22 | blue | NULL 3 | blue | NULL 10 | red | NULL 4 | blue | NULL 5 | red | NULL 11 | blue | NULL 23 | blue