我想知道我使用的4个查询如何合并到一个查询中。我能够查询数据集中表示的所有日期以及每个特定日期的点击次数。理想情况下，我也可以从该查询中获得安装次数（每天），总费用（每天）和备注（每天）。
我已经考虑过如何实现这一点，但由于我是MySQL的新手，因此没有提出任何完整的解决方案。有没有一种从多个表中提取数据的好方法？
$days = mysqli_query($link, "
SELECT
t1.date,
t1.clicks
FROM (SELECT
date_format(date_sub(ic.click_utc, INTERVAL 7 HOUR), '%Y-%m-%d') as date,
count(distinct ic.txid) as clicks
FROM users_clicks ic
GROUP BY date_format(date_sub(click_utc, INTERVAL 7 HOUR), '%Y-%m-%d')
ORDER BY date DESC) t1
WHERE date >= '2014-06-28'");
while ($day = mysqli_fetch_assoc($days)) {
$date = $day['date'];
$day_clicks = $day['clicks'];
$day_installs = mysqli_fetch_row(mysqli_query($link, sprintf("SELECT count(txid) FROM (SELECT txid FROM users_installs WHERE date_format(date_sub(click_utc, INTERVAL 7 HOUR), '%%Y-%%m-%%d') = '%s' GROUP BY txid) table1", $day['date'])));
$day_cost = mysqli_fetch_row(mysqli_query($link, sprintf("SELECT sum(earnings) FROM (SELECT max(cost) as earnings FROM users_clicks WHERE date_format(date_sub(click_utc, INTERVAL 7 HOUR), '%%Y-%%m-%%d') = '%s' GROUP BY txid) table1", $day['date'])));
$note = mysqli_fetch_assoc(mysqli_query($link, sprintf("SELECT * FROM reporting_notes WHERE date_format(date_sub(timestamp, INTERVAL 7 HOUR), '%%Y-%%m-%%d') = '%s' LIMIT 1", $day['date'])));
}
以下是表格的结构：
Users_clicks：
txid | click_utc | cost
12t3 | 2014-08-19 07:08:47 | 0.50
27a5 | 2014-08-18 03:28:03 | 0.25
48a5 | 2014-08-17 12:55:23 | 0.25
Users_installs：
txid | click_utc
1o23 | 2014-08-19 07:08:47
1ee3 | 2014-08-17 11:10:53
Reporting_notes：
timestamp | note
2014-08-19 07:08:47 | "hey"
2014-08-17 03:02:41 | "hey"
所需的输出：点击次数，安装次数，总费用以及数据集中每个日期的任何备注
答案 0 :(得分：2)
首先：MySQL能够处理命名的时区，但您需要首先在时区上填充信息表。请参阅CONVERT_TZ的文档作为起点。
由于您的表似乎不相关（即没有包含所有txid的主表，...），您可能最好使用接近于触发单独查询的子查询开始。
SELECT
DATE(CONVERT_TZ(click_utc, '+00:00', '-07:00')) AS date,
COUNT(*) AS clicks,
SUM(cost) AS costs
FROM users_clicks
GROUP BY DATE(CONVERT_TZ(click_utc, '+00:00', '-07:00'));
SELECT
DATE(CONVERT_TZ(min_click_utc, '+00:00', '-07:00')) AS date,
COUNT(*) AS clicks,
SUM(max_costs) AS costs
FROM (SELECT
txid,
MIN(click_utc) AS min_click_utc,
MAX(cost) AS max_costs
FROM users_clicks
GROUP BY txid) distinct_txids
GROUP BY DATE(CONVERT_TZ(min_click_utc, '+00:00', '-07:00'))
SELECT
DATE(CONVERT_TZ(click_utc, '+00:00', '-07:00')) AS date,
COUNT(*) AS installs
FROM users_installs
GROUP BY DATE(CONVERT_TZ(click_utc, '+00:00', '-07:00'));
SELECT
DATE(CONVERT_TZ(min_click_utc, '+00:00', '-07:00')) AS date,
COUNT(*) AS installs
FROM (SELECT
txid,
MIN(click_utc) AS min_click_utc
FROM users_installs
GROUP BY txid) distinct_txids
GROUP BY DATE(CONVERT_TZ(min_click_utc, '+00:00', '-07:00'));
（请注意，GROUP_CONCAT默认只返回1024个字符。可以通过将group_concat_max_len设置为更高的值来更改：
SELECT
DATE(CONVERT_TZ(timestamp, '+00:00', '-07:00')) AS date,
COUNT(*) AS note_count,
GROUP_CONCAT(note SEPARATOR ', ') AS notes
FROM reporting_notes
GROUP BY DATE(CONVERT_TZ(timestamp, '+00:00', '-07:00'));
如果您想立即获取所有内容，您需要先获得一个共同的日期池，因为MySQL只有LEFT或RIGHT OUTER JOIN s，而不是FULL OUTER JOIN s：
SELECT DISTINCT
date
FROM (
SELECT
DATE(CONVERT_TZ(click_utc, '+00:00', '-07:00')) AS date
FROM users_clicks
UNION SELECT
DATE(CONVERT_TZ(click_utc, '+00:00', '-07:00')) AS date
FROM users_installs
UNION SELECT
DATE(CONVERT_TZ(timestamp, '+00:00', '-07:00')) AS date
FROM reporting_notes) dates;
然后你可以将它们全部合并到
中SELECT
dates.date,
clicks.clicks,
clicks.costs,
installs.installs,
notes.note_count,
notes.notes
FROM (SELECT DISTINCT
date
FROM (
SELECT
DATE(CONVERT_TZ(click_utc, '+00:00', '-07:00')) AS date
FROM users_clicks
UNION SELECT
DATE(CONVERT_TZ(click_utc, '+00:00', '-07:00')) AS date
FROM users_installs
UNION SELECT
DATE(CONVERT_TZ(timestamp, '+00:00', '-07:00')) AS date
FROM reporting_notes) data) dates
LEFT JOIN (SELECT
DATE(CONVERT_TZ(click_utc, '+00:00', '-07:00')) AS date,
COUNT(*) AS clicks,
SUM(cost) AS costs
FROM users_clicks
GROUP BY DATE(CONVERT_TZ(click_utc, '+00:00', '-07:00'))) clicks ON clicks.date = dates.date
LEFT JOIN (SELECT
DATE(CONVERT_TZ(click_utc, '+00:00', '-07:00')) AS date,
COUNT(*) AS installs
FROM users_installs
GROUP BY DATE(CONVERT_TZ(click_utc, '+00:00', '-07:00'))) installs ON installs.date = dates.date
LEFT JOIN (SELECT
DATE(CONVERT_TZ(timestamp, '+00:00', '-07:00')) AS date,
COUNT(*) AS note_count,
GROUP_CONCAT(note SEPARATOR ', ') AS notes
FROM reporting_notes
GROUP BY DATE(CONVERT_TZ(timestamp, '+00:00', '-07:00'))) notes ON notes.date = dates.date;
如果您知道，在安装发生的每一天，还有一个点击，您可以使用点击查询作为日期池，查询会变得更容易。无论如何，我可能会运行一个单独的查询来获取每天的注释，以便能够对文本采取行动。
此查询将确保users_installs和users_clicks中的每个txid仅在其发生的最早日期计数一次。由于有两个额外的子子查询，性能将（至少）略差。如果txids已经不同，我会建议不要这样做。如果您开始在子查询中过滤日期，则可以提高性能。
SELECT
dates.date,
clicks.clicks,
clicks.costs,
installs.installs,
notes.note_count,
notes.notes
FROM (SELECT DISTINCT
date
FROM (
SELECT
DATE(CONVERT_TZ(click_utc, '+00:00', '-07:00')) AS date
FROM users_clicks
UNION SELECT
DATE(CONVERT_TZ(click_utc, '+00:00', '-07:00')) AS date
FROM users_installs
UNION SELECT
DATE(CONVERT_TZ(timestamp, '+00:00', '-07:00')) AS date
FROM reporting_notes) data) dates
LEFT JOIN (SELECT
DATE(CONVERT_TZ(min_click_utc, '+00:00', '-07:00')) AS date,
COUNT(*) AS clicks,
SUM(max_costs) AS costs
FROM (SELECT
txid,
MIN(click_utc) AS min_click_utc,
MAX(cost) AS max_costs
FROM users_clicks
GROUP BY txid) distinct_txids
GROUP BY DATE(CONVERT_TZ(min_click_utc, '+00:00', '-07:00'))) clicks ON clicks.date = dates.date
LEFT JOIN (SELECT
DATE(CONVERT_TZ(min_click_utc, '+00:00', '-07:00')) AS date,
COUNT(*) AS installs
FROM (SELECT
txid,
MIN(click_utc) AS min_click_utc
FROM users_installs
GROUP BY txid) distinct_txids
GROUP BY DATE(CONVERT_TZ(min_click_utc, '+00:00', '-07:00'))) installs ON installs.date = dates.date
LEFT JOIN (SELECT
DATE(CONVERT_TZ(timestamp, '+00:00', '-07:00')) AS date,
COUNT(*) AS note_count,
GROUP_CONCAT(note SEPARATOR ', ') AS notes
FROM reporting_notes
GROUP BY DATE(CONVERT_TZ(timestamp, '+00:00', '-07:00'))) notes ON notes.date = dates.date;
答案 1 :(得分：1)
认为这需要加入子查询。
获取所使用的各种日期的一个子查询，然后将其与子查询相关联以获取点击次数和次点数，另一个获取安装次数： -
SELECT sub0.aDate, click_count, click_cost, install_count, GROUP_CONCAT(reporting_notes.note)
FROM
(
SELECT DATE(click_utc) AS aDate
FROM users_clicks
UNION
SELECT DATE(click_utc)
FROM users_installs
UNION
SELECT DATE(timestamp)
FROM reporting_notes
) sub0
LEFT OUTER JOIN
(
SELECT DATE(click_utc) AS aDate, COUNT(txid) AS click_count, SUM(cost) AS click_cost
FROM users_clicks
GROUP BY aDate
) sub1
ON sub0.aDate = sub1.aDate
LEFT OUTER JOIN
(
SELECT DATE(click_utc) AS aDate, COUNT(txid) AS install_count
FROM users_installs
GROUP BY aDate
) sub2
ON sub0.aDate = sub2.aDate
LEFT OUTER JOIN reporting_notes
ON sub0.aDate = DATE(reporting_notes.timestamp)
GROUP BY sub0.aDate, click_count, click_cost, install_count
如果你只想要独特的笔记并且不需要总和，这可以在没有子查询的情况下完成。