Question

我有一个可以根据需要运行的查询...但是，我想将其转换为临时表...当我添加“ CREATE TEMPORARY TABLE temptable”行时，phpmyadmin中弹出一个错误，提示该子查询返回多于1行。有什么想法吗？

CREATE TEMPORARY TABLE temptable
SELECT *, 
(SELECT judgement FROM wwlpredictedoveralljudgements p1 WHERE p1.pupilID=x.pupilID && p1.subject=x.subject 
 && p1.dateAchieved=(SELECT MAX(p2.dateAchieved) FROM wwlpredictedoveralljudgements p2 WHERE p1.pupilID=p2.pupilID && p1.subject=p2.subject
                    && p2.dateAchieved>'2018-08-25 00:00:00' && p2.dateAchieved<'2018-12-31 00:00:00')) AS endOfTerm1,
(SELECT judgement FROM wwlpredictedoveralljudgements p4 WHERE p4.pupilID=x.pupilID && p4.subject=x.subject 
 && p4.dateAchieved=(SELECT MAX(p5.dateAchieved) FROM wwlpredictedoveralljudgements p5 WHERE p4.pupilID=p5.pupilID && p4.subject=p5.subject
                    && p5.dateAchieved>'2018-08-25 00:00:00' && p5.dateAchieved<'2019-03-28 00:00:00')) AS endOfTerm2

FROM (
SELECT u.legalFirstName, u.legalSurname, u.form, p3.pupilID, p3.subject
FROM wwlpredictedoveralljudgements p3
LEFT JOIN users u USING(pupilID)
WHERE u.ncYear<7
GROUP BY p3.pupilID, p3.subject
)x

Answer 1

如果您的子查询返回的行多，那么您应该或使用IN运算符或将结果减少到限制1之内，例如：

    CREATE TEMPORARY TABLE temptable
    SELECT *
      , ( SELECT judgement 
          FROM wwlpredictedoveralljudgements p1 
          WHERE p1.pupilID=x.pupilID 
          AND p1.subject=x.subject 
          AND p1.dateAchieved IN ( 
            SELECT MAX(p2.dateAchieved) 
            FROM wwlpredictedoveralljudgements p2 
            WHERE p1.pupilID=p2.pupilID 
            AND p1.subject=p2.subject
            AND p2.dateAchieved>'2018-08-25 00:00:00' 
            AND p2.dateAchieved<'2018-12-31 00:00:00')) AS endOfTerm1
      , ( SELECT judgement 
          FROM wwlpredictedoveralljudgements p4 
          WHERE p4.pupilID=x.pupilID 
          AND p4.subject=x.subject 
          AND p4.dateAchieved IN (
            SELECT MAX(p5.dateAchieved) 
            FROM wwlpredictedoveralljudgements p5 
            WHERE p4.pupilID=p5.pupilID 
            AND p4.subject=p5.subject
            AND p5.dateAchieved>'2018-08-25 00:00:00' 
            AND p5.dateAchieved<'2019-03-28 00:00:00')) AS endOfTerm2

    FROM (
      SELECT u.legalFirstName, u.legalSurname, u.form, p3.pupilID, p3.subject
      FROM wwlpredictedoveralljudgements p3
      LEFT JOIN users u USING(pupilID)
      WHERE u.ncYear<7
      GROUP BY p3.pupilID, p3.subject
    ) x

或

    CREATE TEMPORARY TABLE temptable
    SELECT *
      , ( SELECT judgement 
          FROM wwlpredictedoveralljudgements p1 
          WHERE p1.pupilID=x.pupilID 
          AND p1.subject=x.subject 
          AND p1.dateAchieved = ( 
            SELECT MAX(p2.dateAchieved) 
            FROM wwlpredictedoveralljudgements p2 
            WHERE p1.pupilID=p2.pupilID 
            AND p1.subject=p2.subject
            AND p2.dateAchieved>'2018-08-25 00:00:00' 
            AND p2.dateAchieved<'2018-12-31 00:00:00'
            LIMIT 1 )
            LIMIT 1 ) AS endOfTerm1
      , ( SELECT judgement 
          FROM wwlpredictedoveralljudgements p4 
          WHERE p4.pupilID=x.pupilID 
          AND p4.subject=x.subject 
          AND p4.dateAchieved =  (
            SELECT MAX(p5.dateAchieved) 
            FROM wwlpredictedoveralljudgements p5 
            WHERE p4.pupilID=p5.pupilID 
            AND p4.subject=p5.subject
            AND p5.dateAchieved>'2018-08-25 00:00:00' 
            AND p5.dateAchieved<'2019-03-28 00:00:00'
            LIMIT 1 )
            LIMIT 1 ) AS endOfTerm2

    FROM (
      SELECT u.legalFirstName, u.legalSurname, u.form, p3.pupilID, p3.subject
      FROM wwlpredictedoveralljudgements p3
      LEFT JOIN users u USING(pupilID)
      WHERE u.ncYear<7
      GROUP BY p3.pupilID, p3.subject
    ) x

由于子查询多行而导致临时表错误

1 个答案: