What is the ratio of players with batting hands of left and right?
batting hands of left refers to Batting_hand = 'Left-hand bat'; right refers to Batting_hand = 2; ratio refers to DIVIDE(COUNT(Batting_hand = 'Right-hand bat'), COUNT(Batting_hand = 2))
SELECT CAST(SUM(CASE WHEN T2.Batting_hand = 'Left-hand bat' THEN 1 ELSE 0 END) AS REAL) / SUM(CASE WHEN T2.Batting_hand = 'Right-hand bat' THEN 1 ELSE 0 END) FROM Player AS T1 INNER JOIN Batting_Style AS T2 ON T1.Batting_hand = T2.Batting_Id