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1CREATE TEMPORARY TABLE IF NOT EXISTS c AS (
2    SELECT x, y FROM (
3        SELECT 0 as x UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 
4        UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9
5    ) x
6    CROSS JOIN (
7    SELECT 0 as y UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 
8            UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9
9    ) y
10);
11	
12SET @size = 2 - 1;
13	
14SELECT * FROM c WHERE NOT EXISTS (
15    SELECT 1 FROM t WHERE (
16        (x >= x1 AND x <= x2) 
17        OR (x + @size >= x1 AND x + @size <= x2)
18        OR (x1 >= x AND x1 <= x + @size)
19        OR (x2 >= x AND x2 <= x + @size)
20    ) AND (
21        (y >= y1 AND y <= y2) 
22        OR (y + @size >= y1 AND y + @size <= y2)
23        OR (y1 >= y AND y1 <= y + @size)
24        OR (y2 >= y AND y2 <= y + @size)
25    )
26)
27AND x < 10 - @size
28AND y < 10 - @size
29ORDER BY x, y
30LIMIT 1;