[英]MYSQL divide results from multiple subqueries with multiple rows
我有兩個查詢,第一個查詢生成一個表,例如
SELECT COUNT(channel) AS messages FROM Chats WHERE message LIKE '%word%' GROUP BY UNIX_TIMESTAMP(time) DIV 3600
+-----+
| 123 |
| 127 |
| 332 |
| 219 |
+-----+
第二個
SELECT COUNT(channel) AS messages FROM Chats GROUP BY UNIX_TIMESTAMP(time) DIV 3600
+-----+
| 222 |
| 579 |
| 590 |
| 377 |
+-----+
現在,我想將第一個表中的所有結果除以第二個表中的對應值(結果四舍五入,必須手動計算):
+------+
| 0.55 | #123/222
| 0.46 | #127/279
| 0.56 | #332/590
| 0.58 | #219/377
+------+
這是通過以下查詢完成整個任務的一種方法:
SELECT
(dividendTable.messages / divisorTable.messages) AS result
FROM
(
SELECT
firstTable.messages,
@rn1 := @rn1 + 1 AS row_number
FROM
(
SELECT
COUNT(channel) AS messages
FROM Chats
WHERE message LIKE '%word%'
GROUP BY UNIX_TIMESTAMP(time) DIV 3600
) FirstTable, (SELECT @rn1 := 0) var1
) AS dividendTable
INNER JOIN
(
SELECT
secondTable.messages,
@rn2 := @rn2 + 1 AS row_number
FROM
(
SELECT
COUNT(channel) AS messages
FROM Chats
GROUP BY UNIX_TIMESTAMP(time) DIV 3600
) secondTable, (SELECT @rn2 := 0) var2
) AS divisorTable
ON dividendTable.row_number = divisorTable.row_number;
注意:
如果希望結果四舍五入到小數點后兩位,則使用以下內容作為查詢的第一行:
SELECT
ROUND((dividendTable.messages / divisorTable.messages),2) AS result
警告:您在查詢中未使用任何ORDER BY。 您可能會得到隨機行為。
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.