psycopg2 PSQL SELECT語句返回0L而不是0

Question

我的SELECT語句有意外的結果。

我有以下代碼：

db_cursor.execute("""SELECT player.player_id, player.player_name, 
         COUNT(match.winner_id) as wins, COUNT(match.loser_id + match.winner_id) as total_matches 
         FROM player LEFT JOIN match ON player.player_id = match.winner_id 
         GROUP BY player.player_id 
         ORDER BY wins ASC""") 
results = db_cursor.fetchall() 
print results 

，我得到下面的輸出，當我打印。

[(317, 'Bruno Walton', 0L, 0L), (318, "Boots O'Neal", 0L, 0L), (319, 'Cathy Burton', 0L, 0L), (320, 'Diane Grant', 0L, 0L)] 
[(318, "Boots O'Neal", 0L, 0L), (320, 'Diane Grant', 0L, 0L), (317, 'Bruno Walton', 1L, 1L), (319, 'Cathy Burton', 1L, 1L)] 

什麼是0L和1L？我認爲'L'只適用於非常大的數字，而不是一個數字。

對不起，我是初學者，所以它可能是非常明顯的，但任何幫助，將不勝感激。如果有幫助，這是對錶的PSQL：

CREATE TABLE IF NOT EXISTS player 
(player_id SERIAL PRIMARY KEY, player_name TEXT); 

CREATE TABLE IF NOT EXISTS match 
(match_id SERIAL PRIMARY KEY, winner_id INTEGER references player(player_id), 
loser_id INTEGER references player(player_id)); 

Answer 1

可以轉換運算符添加到查詢即COUNT（match.winner_id）:: int和COUNT（match.loser_id + match.winner_id）:: INT。否則，您將不得不在結果集中投射該列。

db_cursor.execute("""SELECT player.player_id, player.player_name, 
         COUNT(match.winner_id)::int as wins, COUNT(match.loser_id + match.winner_id)::int as total_matches 
         FROM player LEFT JOIN match ON player.player_id = match.winner_id 
         GROUP BY player.player_id 
         ORDER BY wins ASC""")