SQL查詢：檢索具有不同條件的列

我需要從不同表中檢索具有不同條件的多個列。什麼，我有如下SQL查詢：檢索具有不同條件的列

SELECT 
(SELECT COUNT(*) FROM Table1 WHERE Price >= 0 Price < 10) AS 'Group1', 
(SELECT COUNT(*) FROM Table1 WHERE Price >= 10 AND Price < 20) AS 'Group2', 
(SELECT COUNT(*) FROM Table1 WHERE Price >= 20 AND Price < 30) AS 'Group3', 
(SELECT COUNT(*) FROM Table2 WHERE Price >= 0 Price < 10) AS 'Group4', 
(SELECT COUNT(*) FROM Table2 WHERE Price >= 10 AND Price < 20) AS 'Group5', 
(SELECT COUNT(*) FROM Table2 WHERE Price >= 20 AND Price < 30) AS 'Group6'

只是想知道有沒有什麼更好的方式來重組爲上述條件更好的查詢？

來源

2013-04-10 My2ndLovE

有，

SELECT SUM(CASE WHEN Price >= 0 Price < 10 THEN 1 END) AS 'Group1', 
     SUM(CASE WHEN Price >= 10 AND Price < 20 THEN 1 END) AS 'Group2', 
     SUM(CASE WHEN Price >= 20 AND Price < 30 THEN 1 END) AS 'Group3', 
     SUM(CASE WHEN Price >= 0 Price < 10 THEN 1 END) AS 'Group4', 
     SUM(CASE WHEN Price >= 10 AND Price < 20 THEN 1 END) AS 'Group5', 
     SUM(CASE WHEN Price >= 20 AND Price < 30 THEN 1 END) AS 'Group6' 
FROM table2

來源

2013-04-10 06:01:56

爲什麼好，有什麼區別？問題中還有2個表格。 – Alex 2013-04-10 06:10:23

@Alexey它只會傳遞一次表格，而不是調用6'SELECT'語句 – 2013-04-10 06:12:30

@J W但由於價格限制，它不會執行全面掃描。所以在一起看起來都一樣。 – Alex 2013-04-10 06:14:17

用j W.加起來table1的上述精彩查詢

SELECT SUM(CASE WHEN T1.Price >= 0 Price < 10 THEN 1 END) AS 'Group1', 
     SUM(CASE WHEN T1.Price >= 10 AND Price < 20 THEN 1 END) AS 'Group2', 
     SUM(CASE WHEN T1.Price >= 20 AND Price < 30 THEN 1 END) AS 'Group3', 
     SUM(CASE WHEN T2.Price >= 0 Price < 10 THEN 1 END) AS 'Group4', 
     SUM(CASE WHEN T2.Price >= 10 AND Price < 20 THEN 1 END) AS 'Group5', 
     SUM(CASE WHEN T2.Price >= 20 AND Price < 30 THEN 1 END) AS 'Group6' 
FROM table1 T1, table2 T2

來源

2013-04-10 07:09:22 user2135380

太棒了。謝謝。 – My2ndLovE 2013-04-10 07:25:36

快樂...... – user2135380 2013-04-10 07:33:14

SQL查詢：檢索具有不同條件的列

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