java - ユニオン演算子を使用してSQLクエリを連結する方法

Question

String Query="select * from recommendation.sports WHERE feed LIKE'%"+s1+"%'

    UNION "select * from recommendation.software  WHERE feed LIKE '%"+s1+"%'

    UNION "select * from recommendation.website   WHERE feed LIKE '%"+s1+"%'

    UNION "select * from recommendation.others    WHERE feed LIKE '%"+s1+"%'

    UNION "select * from recommendation.business  WHERE feed LIKE '%"+s1+"%'";

Answer 1

多分あなたはこれを意味しますか？

String Query = "select * from recommendation.sports WHERE feed LIKE '%" + s1 + "%' " +
                "UNION " +
                "select * from recommendation.software  WHERE feed LIKE '%" +s1+ "%' " +
                "UNION " +
                "select * from recommendation.website   WHERE feed LIKE '%" +s1+" %' " +
                "UNION " +
                "select * from recommendation.others    WHERE feed LIKE '%"+s1+"%' " +
                "UNION " +
                "select * from recommendation.business  WHERE feed LIKE '%" +s1+ "%'" ;

PreparedStatementsただし、を避けるためにクエリで使用することをお勧めしますSQL Injection。

String Query = "select * from recommendation.sports WHERE feed LIKE CONCAT('%', ?, '%') " +
                "UNION " +
                "select * from recommendation.software  WHERE feed LIKE CONCAT('%', ?, '%') " +
                "UNION " +
                "select * from recommendation.website   WHERE feed LIKE CONCAT('%', ?, '%') " +
                "UNION " +
                "select * from recommendation.others    WHERE feed LIKE CONCAT('%', ?, '%')  " +
                "UNION " +
                "select * from recommendation.business  WHERE feed LIKE CONCAT('%', ?, '%')" ;

PreparedStatement pstmt = con.prepareStatement(Query);
pstmt.setString(1, s1);
pstmt.setString(2, s1);
pstmt.setString(3, s1);
pstmt.setString(4, s1);
pstmt.setString(5, s1);
ResultSet _result = pstmt.executeQuery();

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Answer 2

これを試して：

 String Query="select * from recommendation.sports WHERE feed LIKE'%"+s1+"%'

    UNION select * from recommendation.software  WHERE feed LIKE '%"+s1+"%'

    UNION select * from recommendation.website   WHERE feed LIKE '%"+s1+"%'

    UNION select * from recommendation.others    WHERE feed LIKE '%"+s1+"%'

    UNION select * from recommendation.business  WHERE feed LIKE '%"+s1+"%'";

Answer 3

若干の変更がありますので、ご確認ください。

String Query="select * from recommendation.sports WHERE feed LIKE \'%"+s1+"%\'

    UNION select * from recommendation.software  WHERE feed LIKE \'%"+s1+"%\'

    UNION select * from recommendation.website   WHERE feed LIKE \'%"+s1+"%\'

    UNION select * from recommendation.others    WHERE feed LIKE \'%"+s1+"%\'

    UNION select * from recommendation.business  WHERE feed LIKE \'%"+s1+"%\'";

これを試して、うまくいくかどうか教えてください。