錯誤與正則表達式SELECT CASE

Question

我寫在T-SQL下面的查詢的SQL Server

SELECT 
    CASE 
     WHEN ADDR_LINE_1 REGEXP '^[0-9]' 
     THEN SUBSTRING(ADDR_LINE_1,1,CHARINDEX(' ',ADDR_LINE_1)) 
     ELSE NULL 
    END AS HOUSE_NUMBER 
FROM CUSTOMER 

我想的是，如果該列ADDR_LINE_1以數字開頭，我想提取從HOUSE_NUMBER它。但現在我的查詢給出了一個解析錯誤。如果我用LIKE替換REGEXP這個詞，解析錯誤消失，但我總是爲HOUSE_NUMBER獲得NULL。我的查詢的正確語法是什麼？

Answer 1

你可以使用ISNUMERIC和LEFT這個樣子。

SELECT 
    CASE WHEN ISNUMERIC(LEFT(ADDR_LINE_1, 1)) = 1 
    THEN SUBSTRING(ADDR_LINE_1, 1, CHARINDEX(' ', ADDR_LINE_1)) 
    ELSE NULL 
    END AS HOUSE_NUMBER 
FROM CUSTOMER 

Answer 2

如何使用LIKE

SELECT 
    CASE 
     WHEN ADDR_LINE_1 Like '%[0-9]%' 
     THEN SUBSTRING(ADDR_LINE_1,1,CHARINDEX(' ',ADDR_LINE_1)) 
     ELSE NULL 
    END AS HOUSE_NUMBER 
FROM CUSTOMER