Question

编辑：一直使用SQLiteBrowser作为IDE \ Tool

不是SQLite的常用用户 - 请原谅我的无知。下面的查询是更大查询的一部分;

SELECT DISTINCT T1.Material AS "Diameter", 
                T2.sLength  AS "0-110mm", 
                T3.sLength  AS "110-160mm", 
                T4.sLength  AS "225-300mm", 
                T5.sLength  AS "300-450mm", 
                T6.sLength  AS "450-600mm", 
                T7.sLength  AS "600mm-" 
FROM   "mycte" T1 
       LEFT JOIN "mycte" T2 
              ON T1.Material = T2.Material 
                 AND T2.Diameter = "0-110mm" 
       LEFT JOIN "mycte" T3 
              ON T1.Material = T3.Material 
                 AND T3.Diameter = "110-160mm" 
       LEFT JOIN "mycte" T4 
              ON T1.Material = T4.Material 
                 AND T4.Diameter = "225-300mm" 
       LEFT JOIN "mycte" T5 
              ON T1.Material = T5.Material 
                 AND T5.Diameter = "300-450mm" 
       LEFT JOIN "mycte" T6 
              ON T1.Material = T6.Material 
                 AND T6.Diameter = "450-600mm" 
       LEFT JOIN "mycte" T7 
              ON T1.Material = T7.Material 
                 AND T7.Diameter = "600mm-" 
WHERE  T1.Material <> ''

虽然我在别名中使用带有单个连字符\ _减号的别名，但字段返回空。如果我重命名别名＆＃34; 0-110mm＆＃34;到＆＃34; 0--110mm＆＃34;，列的字段返回数据。看起来似乎只有一个连字符\_dé正在搞乱。

有什么想法吗？提前谢谢。

Answer 1

最好的我已经设法提出这个。只需要处理名称中的尾随空格。

SELECT DISTINCT
     T1.Material AS "Diameter"
    ,T2.sLength  AS [0-110mm ]
    ,T3.sLength  AS [110-160mm ]        
    ,T4.sLength  AS [160-225mm ]
    ,T5.sLength  AS [225-300mm ]    
    ,T6.sLength  AS [300-450mm ]    
    ,T7.sLength  AS [450-600mm ]
    ,T8.sLength  AS [600mm- ]   
FROM "MyCTE" T1
LEFT
JOIN "MyCTE" T2 ON T1.Material = T2.Material AND T2.Diameter = "0-110mm"
LEFT
JOIN "MyCTE" T3 ON T1.Material = T3.Material AND T3.Diameter = "110-160mm"
LEFT
JOIN "MyCTE" T4 ON T1.Material = T4.Material AND T4.Diameter = "160-225mm"
LEFT
JOIN "MyCTE" T5 ON T1.Material = T5.Material AND T5.Diameter = "225-300mm"       
LEFT
JOIN "MyCTE" T6 ON T1.Material = T6.Material AND T6.Diameter = "300-450mm"
LEFT
JOIN "MyCTE" T7 ON T1.Material = T7.Material AND T7.Diameter = "450-600mm"
LEFT
JOIN "MyCTE" T8 ON T1.Material = T8.Material AND T8.Diameter = "600mm-"

Answer 2

我不确定您使用的是哪个版本的SQLite，但以下小提示演示了您的初始方法是否正常工作：

http://sqlfiddle.com/#!7/20222/1

CREATE TABLE test 
  ( 
     col1 VARCHAR(100) 
  ); 

INSERT INTO test 
            (col1) 
SELECT 'foo' 

SELECT col1 AS "col-1" 
FROM   test

Answer 3

不要使用双引号或方括号作为别名。请改用单引号。这可能会解决问题。前几天我遇到了类似的问题，不一样但是相似。

https://www.sqlite.org/lang_keywords.html

＆＃39;关键字＆＃39;单引号中的关键字是字符串文字。＆＃34;关键字＆＃34;双引号中的关键字是标识符。 [keyword]方括号中的关键字是标识符。这不是标准的SQL。此引用机制由MS Access和SQL Server使用，并包含在SQLite中以实现兼容性。

SQLite - 在列别名中使用连字符

3 个答案: