Question

我必须使用子查询从下表中显示Mothers_name，AGE和平均年龄？

我试过

SELECT Mothers_name,
       Age,
       AVG(Age)
FROM   MOTHERS
WHERE  Age > (SELECT AVG(Age)
              FROM   MOTHERS)

但这不显示平均年龄。

+-----------+--------------+-----+------+
| MothersID | Mothers_name | Age | KIDS |
+-----------+--------------+-----+------+
|        41 | Kirke        |  19 |    1 |
|        44 | Kiisu        |  19 |    1 |
|        26 | Mormela      |  20 |    2 |
|        45 | Merka        |  20 |    1 |
|        19 | Zandra       |  20 |    1 |
|        24 | Kiisuke      |  20 |    1 |
|        18 | Kristlin     |  21 |    1 |
|         1 | Imbi         |  21 |    1 |
|        10 | Kiki         |  22 |    1 |
|         8 | Lilleke      |  22 |    3 |
|        29 | Silja        |  22 |    1 |
|        17 | Plikake      |  23 |    1 |
|        36 | Fly          |  24 |    2 |
|        37 | Blanka       |  24 |    1 |
|        16 | Moonika      |  24 |    1 |
|        20 | Pisikeingel  |  24 |    1 |
|        27 | Krista       |  24 |    2 |
|        32 | Margariita   |  24 |    2 |
|        13 | Signeke      |  25 |    1 |
|        40 | Mari         |  25 |    1 |
|        47 | Maiki        |  26 |    1 |
|        31 | Liisa-Lota   |  26 |    1 |
|         2 | Rapunzel     |  26 |    2 |
|        46 | Pille        |  26 |    1 |
|        14 | Eveke        |  26 |    2 |
|        21 | Jessika      |  27 |    1 |
|        48 | Lilleke      |  27 |    2 |
|        15 | Nadja        |  27 |    2 |
|        23 | Triinu       |  27 |    2 |
|        33 | Annika       |  27 |    1 |
|        35 | Nella        |  28 |    2 |
|         6 | Miili        |  28 |    1 |
|        34 | Piibe        |  28 |    2 |
|        11 | Katriin      |  28 |    2 |
|         5 | Kurr         |  28 |    1 |
|        22 | Kriste       |  28 |    3 |
|         4 | Kristall     |  29 |    1 |
|        38 | Roosi        |  29 |    2 |
|        39 | Ave          |  29 |    3 |
|        50 | Katrin       |  29 |    2 |
|        12 | Zipsik       |  29 |    1 |
|        43 | Tups         |  30 |    1 |
|         3 | Katariina    |  30 |    1 |
|        28 | Carmen       |  30 |    2 |
|        49 | Viki         |  30 |    2 |
|        30 | Viivi        |  31 |    1 |
|         7 | Patsike      |  31 |    3 |
|        42 | Marja        |  32 |    1 |
|         9 | Margareth    |  32 |    2 |
|        25 | Ade          |  34 |    2 |
+-----------+--------------+-----+------+

Answer 1

如果您想选择具有相同名称的母亲的平均年龄，您应该按名称字段分组：

SELECT Mothers_name, Age, AVG(Age) FROM MOTHERS 
WHERE Age > (SELECT AVG(Age) FROM MOTHERS) 
GROUP BY Mothers_name;

问题是，我没有在数据集中看到任何重复。如果是这种情况，年龄和平均年龄将是相同的值。你能澄清一下你期望的结果吗？

Answer 2

尝试类似

的内容

SELECT * FROM (SELECT Mothers_name, Age,
   (SELECT AVG(Age) FROM MOTHERS) as total_avg
FROM MOTHERS) as tmp WHERE age > total_avg

如何使用子查询显示AVG（AGE）？

2 个答案: