列是模棱两可的错误

Question

请使用以下查询帮助解决问题：

$sql = "SELECT email_id as name, competition_id, end_date FROM " . DB_PREFIX . "competition_winners, competition WHERE". DB_PREFIX . " competition.competition_id = ". DB_PREFIX ."competition_winners.competition_id";

我收到以下错误： 注意：错误：字段列表中的列'competition_id'不明确 错误号：1052 我正在使用opencart。我该如何解决？

Answer 1

更多表的列名相同，为competition_id。

尝试在查询中添加前缀：

$sql = "SELECT email_id as name, c.competition_id as competition_id, end_date FROM " . DB_PREFIX . "competition_winners cw, competition c WHERE". DB_PREFIX . " competition.competition_id = ". DB_PREFIX ."competition_winners.competition_id";

Answer 2

由于您的列competition_id位于多个表中，因此您需要使用表alias作为前缀以避免错误

SELECT competition_winners.email_id as name, competition.competition_id, competition.end_date 
FROM " . DB_PREFIX . "competition_winners as competition_winners, 
     ". DB_PREFIX . "competition as competition 
WHERE competition.competition_id = competition_winners.competition_id";

Answer 3

试试这个：

 $sql = "SELECT email_id as name, c.competition_id, end_date FROM " . DB_PREFIX . "competition_winners cw, competition  c WHERE cw.competition_id = c.competition_id";

错误的原因是两个表都有'competition_id'字段。所以你需要指定category_id字段的表名。