在查询中使用MYSQL条件语句和变量
Hi似乎无法在Im之后构建MYSQL查询 假设我有两列结果:1个浏览器名称和2个浏览器计数 更复杂的是,一旦达到总数的90%,我想将所有其他浏览器重命名为其他浏览器,并相应地标记剩余的百分比 我知道在开始主语句之前,我可以将总计数作为一个变量:在查询中使用MYSQL条件语句和变量,mysql,conditional-statements,Mysql,Conditional Statements,Hi似乎无法在Im之后构建MYSQL查询 假设我有两列结果:1个浏览器名称和2个浏览器计数 更复杂的是,一旦达到总数的90%,我想将所有其他浏览器重命名为其他浏览器,并相应地标记剩余的百分比 我知道在开始主语句之前,我可以将总计数作为一个变量: SELECT @total := COUNT(id) FROM browser_table WHERE start LIKE "2010%"; 然后我可以按浏览器对结果进行分组: SELECT browser, COUNT(id) AS visits
SELECT @total := COUNT(id) FROM browser_table WHERE start LIKE "2010%";
然后我可以按浏览器对结果进行分组:
SELECT browser, COUNT(id) AS visits
FROM browser_table
WHERE start LIKE "2010%"
GROUP BY browser
我知道我需要敲入一个case语句和一个计数器变量来对列进行排序,但不确定如何在上述查询中实现:
CASE
WHEN counter >= 0.9* @total THEN 'other'
ELSE browser
END AS browser;
希望这有意义?感谢您抽出时间……这里有一种方法
您可以根据计算运行总数。例如:
SET @rt := 0;
SELECT
browser,
visits,
(@rt := @rt + visits) AS running_total
FROM
(
SELECT
browser,
COUNT(id) AS visits
FROM
browser_table
WHERE
start LIKE '2010%'
GROUP BY
browser
ORDER BY
visits DESC
) AS sq
;
一旦你准备好了,你可以在此基础上创建一个“其他”类别:
SET @threshold := (SELECT COUNT(id) FROM browser_table WHERE start LIKE '2010%') * 0.90;
SET @rt := 0;
SELECT
browser,
SUM(visits) AS total_visits
FROM
(
SELECT
IF (@rt < @threshold, browser, 'Other') AS browser,
visits,
(@rt := @rt + visits) AS running_total
FROM
(
SELECT
browser,
COUNT(id) AS visits
FROM
browser_table
WHERE
start LIKE '2010%'
GROUP BY
browser
) AS sq1
ORDER BY
visits DESC
) AS sq2
GROUP BY
browser
ORDER BY
total_visits DESC
;