Question

由于ClickHouse不支持查询的WITH子句，因此在实现用于计算MAU的查询时遇到了麻烦（每月活跃用户每天都在计算，而30天范围也在每天移动）。在Postgres中，我会这样做：

 $("#submitboeking").click(function(event) {

        event.preventDefault();


        //Cursisten

            var voornamen = [];
            var achternamen = [];
            var geslachten = [];
            var geboortedata = [];



        $("[id^='txtCursistVoornaam']").each(function() {
            voornamen.push($(this).val());
        });
        $("[id^='txtCursistAchternaam']").each(function() {
            achternamen.push($(this).val());
        });
        $("[id^='radCursistGeslacht']:checked").each(function() {
            geslachten.push($(this).val());
        });
        $("[id^='txtCursistGeboortedatum']").each(function() {
            geboortedata.push($(this).val());
        });

        $.post('/wp-content/themes/tweb/processboeking.php',
         {

                 'geslachten': geslachten,
                 'voornamen': voornamen,
                 'achternamen': achternamen,
                 'geboortedata': geboortedata,

            })
            .done(function(data)
             { 
                //  console.log(data)
                $('#overzicht').html(data);


            }).fail(function(data) {
                alert(response.responseText);
            });

        var li_count = $('.nav-tabs li').length;
        var current_active = $('.nav-tabs li.active').index();
        if (current_active < li_count) {
            $('.nav-tabs li.active').next('li').find('a').attr('data-toggle', 'tab').tab('show');
            var txt = $(".oplselect option:selected").text();
            var val = $(".oplselect option:selected").val();
            $('.showoplnaam').html('Uw selectie: ' + txt);
        }

    });

所需结果看起来像这样

WITH days AS (
  SELECT created_at::DATE AS day,
  FROM events
  WHERE created_at > '2019-04-01'
  GROUP BY 1 
)
SELECT day,
         (SELECT count(distinct user_id)
          FROM events
          WHERE events.created_at::DATE BETWEEN days.day-29 AND days.day
            AND created_at > '2019-04-01'
         ) AS mau
FROM days

Answer 1

您可以尝试这样的事情：

SELECT
    created_at,
    uniqExact(user_id) AS mau
FROM
(
    SELECT
        created_at + n AS created_at,
        user_id
    FROM
    (
        SELECT
            today() - 14 AS created_at,
            123 AS user_id
        UNION ALL
        SELECT
            today() - 20 AS created_at,
            456 AS user_id
    )
    ARRAY JOIN range(30) AS n
)
WHERE created_at <= today()
GROUP BY created_at
FORMAT TSV

2019-04-11  1
2019-04-12  1
2019-04-13  1
2019-04-14  1
2019-04-15  1
2019-04-16  1
2019-04-17  2
2019-04-18  2
2019-04-19  2
2019-04-20  2
2019-04-21  2
2019-04-22  2
2019-04-23  2
2019-04-24  2
2019-04-25  2
2019-04-26  2
2019-04-27  2
2019-04-28  2
2019-04-29  2
2019-04-30  2
2019-05-01  2

21 rows in set. Elapsed: 0.005 sec.

Answer 2

您始终可以内联CTE，例如

SELECT
    d.day,
    COUNT(DISTINCT e.user_id) AS mau
FROM
(
    SELECT created_at::DATE AS day,
    FROM events
    WHERE created_at > '2019-04-01'
    GROUP BY 1 
) d
LEFT JOIN events e
    ON e.created_at::DATE BETWEEN d.day-29 AND d.day
GROUP BY
    d.day;

以上已将CTE替换为子查询别名d。我继续将您的查询重构为使用左联接，替换了您已有的相关子查询。

Answer 3

您还可以创建视图或临时表。

ClickHouse中的每月活跃用户

3 个答案: