創建一個SQL查詢來檢索兩個日期T1和T2之間或T1和T2之外的元素

Question

我想創建一個SQL查詢來檢索兩個日期之間的元素T1和T2 如果我沒有得到結果，我想得到在這些日期之外的結果。 我該怎麼辦只使用SQL

select * from myTable where tmp >= T1 and tmp <= T2 
select * from myTable where tmp < T1 or tmp > T2 

Answer 1

下面的查詢就可以解決這個問題：

SELECT * 
FROM myTable 
WHERE 
(tmp BETWEEN T1 AND T2) 
OR 
((tmp < T1 OR tmp > T2) AND (tmp NOT BETWEEN T1 AND T2)) 

Answer 2

一個類似這樣的查詢應該工作：

(select * from myTable where tmp >= T1 and tmp <= T2) 
UNION 
(select * from myTable WHERE NOT EXISTS (select 1 from myTable where tmp >= T1 and tmp <= T2) AND tmp < T1 or tmp > T2) 

這不是測試，考慮到目前爲止提供的細節。