显示具有相同值的行数

Question

我有一张简单的桌子：

CREATE TABLE clicks
(
    Year UInt16,
    Week UInt8,
    Day UInt8,
    Month UInt8,
    ClickDate Date,
    ClickTime DateTime,
    AdvertId String,
    UserId String,
    Age UInt8,
    Country FixedString(2),
    Gender Enum8('male' = 1, 'female' = 2),
    Ip String
)
ENGINE = MergeTree(ClickDate, (Year, ClickDate), 8192);

是否可以在不重复值的情况下为一列添加一个唯一值的行总和并将它们按ClickDate 分组？例如。我有疑问：

SELECT 
    count() AS Summary, 
    ClickDate, 
    SUM(roundAge(Age) = 17) AS Age_17, 
    SUM(roundAge(Age) = 25) AS Age_25, 
    SUM(roundAge(Age) = 35) AS Age_35, 
    SUM(roundAge(Age) = 45) AS Age_45, 
    SUM(Age = 0) AS Age_empty
FROM clicks 
GROUP BY ClickDate

在这种情况下，我需要复制每个 Age 值

SUM(roundAge(Age) = 17) AS Age_17, 
SUM(roundAge(Age) = 25) AS Age_25

我怎样才能摆脱这种重复？我的期望：

来源数据：

┌──ClickDate─┬─RoundedAge─┐
│ 2016-10-09 │         17 │
└────────────┴────────────┘
┌──ClickDate─┬─RoundedAge─┐
│ 2016-10-09 │         25 │
│ 2016-10-09 │         17 │
│ 2016-10-09 │         45 │
│ 2016-10-09 │         45 │
│ 2016-10-09 │         35 │
│ 2016-10-09 │         45 │
│ 2016-10-09 │         25 │
│ 2016-10-09 │         18 │
│ 2016-10-10 │         25 │
│ 2016-10-10 │         25 │
└────────────┴────────────┘
┌──ClickDate─┬─RoundedAge─┐
│ 2016-10-09 │         17 │
└────────────┴────────────┘

需要的输出：

┌─Summary─┬──ClickDate─┬─Age_17─┬─Age_25─┬─Age_35─┬─Age_45─┬─Age_empty─┐
│      10 │ 2016-10-09 │      3 │      2 │      1 │      3 │         0 │
│       2 │ 2016-10-10 │      0 │      2 │      0 │      0 │         0 │
└─────────┴────────────┴────────┴────────┴────────┴────────┴───────────┘

Answer 1

对不起，我不能为你提供魔法。 但是，这样看起来更好：

SELECT 
    count() AS Summary, 
    ClickDate, 
    countIf(Age = 17), 
    countIf(Age = 25), 
    countIf(Age = 35), 
    countIf(Age = 45), 
    SUM(Age = 0) AS Age_empty
FROM clicks 
GROUP BY ClickDate

我刚刚使用了组合符“If”。我希望这可以帮助你。

Answer 2

你可以使用 CASE WHEN

  SELECT 
  count(*) AS Summary, 
  ClickDate, 
  sum( case when age = 17 then 1 else 0 end),  Age_17,
  sum( case when age = 25 then 1 else 0 end),  Age_25,   
  sum( case when age = 35 then 1 else 0 end),  Age_35,
  sum( case when age = 45 then 1 else 0 end),  Age_45,   
  sum( case when ifnull(age,0) = 0 then 1 else 0 end)  Age_Empty       
  FROM clicks 
  GROUP BY ClickDate

如果你需要范围，你可以在

之间使用

  SELECT 
  count(*) AS Summary, 
  ClickDate, 
  sum( case when age between 1  and 17 then 1 else 0 end),  Age_17,
  sum( case when age between 18 and 25 then 1 else 0 end),  Age_25,   
  sum( case when age between 26 and 35 then 1 else 0 end),  Age_35,
  sum( case when age between 36 and 45 then 1 else 0 end),  Age_45,   
  sum( case when ifnull(age,0) = 0 then 1 else 0 end)  Age_Empty       
  FROM clicks 
  GROUP BY ClickDate