Question

如何在表中选择仅包含所有行的特定值的列？我正在尝试查找这些列，以便对NULL值的值进行更新。在我的专栏中，我有各种各样的值，包括NA

我正在使用SQL Server 2012。

我尝试过：thsi只给我列名。我是否可以为值为＆＃39; NA＆＃39;？

的列添加此条件

SELECT  COLUMN_NAME AS NAMES,COLUMN_DEFAULT
FROM    INFORMATION_SCHEMA.COLUMNS
WHERE   TABLE_SCHEMA = 'dbo'
    AND TABLE_NAME = 'ABC'

我是SQL的初学者。试图找出如何做到这一点。

Answer 1

如果列的min等于max，则该列包含相同的值：

foo = {1:0.001,2:2.097,3:1.093,4:5.246}
foo.pop(2)

new_foo = {i: value for i, (_, value) in enumerate(sorted(foo.items()), start=1)}

print new_foo

使用动态查询：

foo = [0.001, 2.097, 1.093, 5.245]
foo.pop(1) # list indices start at 0
print foo

Answer 2

尝试这个查询

DECLARE @SQLQUERY NVARCHAR(MAX)
declare @tableName varchar(50)
DECLARE @NAME VARCHAR(50)
Declare @ParamDefinition AS NVarchar(2000) 
Set @ParamDefinition =      '@OIM VARCHAR(20)'
SELECT   NAME    
FROM sys.objects  
WHERE [object_id]=@OIM 

 set  @tableName= (SELECT   NAME    
FROM sys.objects  
WHERE [object_id]=@OIM)

SET @NAME=(SELECT C.NAME
FROM  sys.columns c 
  JOIN 
  sys.tables t ON c.object_id = t.object_id 

WHERE  c.name  in (select distinct name
                    from sys.columns           
                    where  object_id=@OIM))

SET @SQLQUERY = ''

SELECT @SQLQUERY = @SQLQUERY + 'UPDATE ' + @tableName + ' SET ' + @NAME + ' = NULL WHERE ' + @NAME + ' = NA ; '  

    PRINT @SQLQUERY
                    Execute sp_Executesql     @SQLQUERY ,  @ParamDefinition, @OIM
end

选择值为NA的列

2 个答案: