Question

在使用varchar列进行比较时，我遇到了使用Between的问题。当我运行时：

SELECT DISTINCT diag_1, Diag_2, Diag_Admit
FROM  Data_Exchange c

WHERE (Diag_1  BETWEEN '29600' and '29606' )

OR (Diag_2 BETWEEN '29600' and '29606')

OR (Diag_Admit between  '29600' and '29606')
------
OR (Diag_1 between '29640' and  '29680')

OR (Diag_2 between '29640' and '29680')

OR (Diag_Admit between '29640' and '29680')

我在结果中显示以下内容： 2967

我不希望这样。如果它没有5位数，则不应显示在结果中。

我该如何解决这个问题？

感谢。

Answer 1

如果您只想将要检查的字符串长度限制为5个字符，则为每列添加where子句：

--Untested(sorry)
SELECT DISTINCT diag_1, Diag_2, Diag_Admit
FROM  Data_Exchange c
WHERE LEN(Diag_1)=5 
AND LEN(Diag_2)=5
AND LEN(Diag_Admit)=5
AND (   Diag_1  BETWEEN '29600' and '29606'
     OR Diag_2 BETWEEN '29600' and '29606'
     OR Diag_Admit between  '29600' and '29606'
     OR Diag_1 between '29640' and  '29680'
     OR Diag_2 between '29640' and '29680'
     OR Diag_Admit between '29640' and '29680')

<强>然而查看varchar列中的所有这些数字让我担心其他事情可能正在发生......

当列是alpha类型时，它按字母顺序排序，因此'2967'应介于'29640'和'29680'之间。

理想情况下，如果列只包含数字，则应将数据类型转换为适当的数字类型，但如果不可行，则此处为解决方法。

按字母顺序排序列表1,2,11,12,13将显示为1,11,12,13,2，如以下SQL所示。

--Test data.
DECLARE @alphaSort AS TABLE(col1 VARCHAR(2))
INSERT INTO @alphaSort VALUES('1')
INSERT INTO @alphaSort VALUES('2')
INSERT INTO @alphaSort VALUES('11')
INSERT INTO @alphaSort VALUES('12')
INSERT INTO @alphaSort VALUES('13')
SELECT col1 FROM @alphaSort ORDER BY col1

--Results:
col1
1
11
12
13
2

如果您希望BETWEEN语句可预测地用于数字，则必须将列转换为数字类型：

SELECT col1 FROM @alphaSort ORDER BY CONVERT(INT,col1)
--Results
col1
1
2
11
12
13

如果列中包含混合数据，则需要使用ISNUMERIC函数来避免以下错误：

--New test data.
DECLARE @alphaSort AS TABLE(col1 VARCHAR(2))
INSERT INTO @alphaSort VALUES('1')
INSERT INTO @alphaSort VALUES('2')
INSERT INTO @alphaSort VALUES('11')
INSERT INTO @alphaSort VALUES('12')
INSERT INTO @alphaSort VALUES('13')
INSERT INTO @alphaSort VALUES('a')

--WITHOUT ISNUMERIC
SELECT col1 FROM @alphaSort ORDER BY CONVERT(INT,col1)

--Results
Msg 245, Level 16, State 1, Line xx
Conversion failed when converting the nvarchar value 'a' to data type int.

--WITH ISNUMERIC
SELECT col1 FROM @alphaSort WHERE ISNUMERIC(col1) = 1 ORDER BY CONVERT(INT,col1)

--Results
col1
1
2
11
12
13

Answer 2

如果您要做的只是测试列的大小是否更大，那么您可以这样做

select * from Data_Exchange 
where len(Diag_1) >4

如果不是，我认为你需要在where子句周围添加另一组（）。我认为它变得混乱

SELECT DISTINCT diag_1, Diag_2, Diag_Admit
FROM  Data_Exchange c
WHERE ((Diag_1  BETWEEN '29600' and '29606' )
   OR (Diag_2 BETWEEN '29600' and '29606')
   OR (Diag_Admit between  '29600' and '29606')
   OR (Diag_1 between '29640' and  '29680')
   OR (Diag_2 between '29640' and '29680')
   OR (Diag_Admit between '29640' and '29680'))

SQL与varchar列之间存在问题

2 个答案: