SELECT aa.*,
bb.meal
FROM table1 aa
INNER JOIN table2 bb
ON aa.tableseat = bb.tableseat AND
aa.weddingtable = bb.weddingtable
INNER JOIN
(
SELECT a.tableSeat
FROM table1 a
INNER JOIN table2 b
ON a.tableseat = b.tableseat AND
a.weddingtable = b.weddingtable
WHERE b.meal IN ('chicken', 'steak')
GROUP by a.tableSeat
HAVING COUNT(DISTINCT b.Meal) = 2
) c ON aa.tableseat = c.tableSeat