Question

在按多个领域分类时,MySQL回到每个集团的滚动行以及总摘要:

CREATE TABLE test (name VARCHAR(50), number TINYINT);
INSERT INTO test VALUES
    ( foo , 1), ( foo , 1), ( foo , 2), ( foo , 3), ( foo , 3),
    ( bar , 1), ( bar , 2), ( bar , 2), ( bar , 2), ( bar , 3),
    ( baz , 1), ( baz , 2), ( bar , 2);
SELECT name, number, COUNT(1) FROM test GROUP BY name, number WITH ROLLUP;

+------+--------+----------+
| name | number | count(1) |
+------+--------+----------+
| bar  |      1 |        1 |
| bar  |      2 |        3 |
| bar  |      3 |        1 |
| bar  |   NULL |        5 |
| baz  |      1 |        1 |
| baz  |      2 |        2 |
| baz  |   NULL |        3 |
| foo  |      1 |        2 |
| foo  |      2 |        1 |
| foo  |      3 |        2 |
| foo  |   NULL |        5 |
| NULL |   NULL |       13 |
+------+--------+----------+

I m not interested in the rollups for foo/bar/baz, only the overall summary. What s the most efficient way to achieve this?

我知道,由于随后添加滚动装置,我可以使用<代码>HAVING。选择名称和编号为的最好办法。 NOT NUL or both NUL?

Answer 1

HA trick trick

SELECT `name`, number, COUNT(1) FROM test GROUP BY `name`, number WITH ROLLUP 
HAVING number IS NOT NULL OR `name` IS NULL;

这过滤了邮电站,但总数除外:

name    number  COUNT(1)
------  ------  --------
bar          1         1
bar          2         4
bar          3         1
baz          1         1
baz          2         1
foo          1         2
foo          2         1
foo          3         2
(NULL)  (NULL)        13

Answer 2

a. 使用亚类,例如:

SELECT * FROM (
  SELECT name, number, COUNT(1) FROM test GROUP BY name, number WITH ROLLUP) t
WHERE name IS NULL OR number IS NULL

您还可能想用适当的案文来改变民族解放军的价值观。

Answer 3

SELECT COALESCE(name,  TOTAL ) as Name, number, COUNT(1) FROM test GROUP BY name, number WITH ROLLUP;

缩略语如果你的数字与否,也可以这样做。

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