SQL Server：從字符串轉換日期和/或時間時轉換失敗

Question

我想檢查一個表的列是否包含空值，如果是，則分配0值。我有問題，因爲那裏存在UniqueIdentifier列。所以我更改我的代碼以分配'0'值。但是現在當有DateTime列時，我遇到了問題。 下面是代碼：

Select @sql = @sql + 'Case when IsNull(i.[' + Column_Name + 
'],''0'') = IsNull(d.[' + Column_name + '],''0'') then '''' 
else ' + quotename(Column_Name, char(39)) + ' + '',''' + ' end +' 
from information_schema.columns 
where table_name = 'Users' and column_name <>'rowguid' and column_name <>'modifieddate' 

另一個失敗的嘗試：

Select @sql = @sql + 
    'Case 
     when IsDate(i.['+Column_Name+']) =1 and IsDate(d.['+Column_Name+']) =1 and IsNull(i.[' + Column_Name + '],1/1/1900) = IsNull(d.[' + Column_name + '],1/1/1900) 
     then '''' 
     when IsNull(i.[' + Column_Name + '],''0'') = IsNull(d.[' + Column_name + '],''0'') 
     then '''' 
     else ' + quotename(Column_Name, char(39)) + ' + '',''' + ' end +' 
from information_schema.columns 
where table_name = 'Users' and column_name <>'rowguid' and column_name <>'modifieddate' 

全碼：

if @Action = 'U' 
BEGIN 
Select @sql = @sql + 
    'Case when IsNull(i.[' + Column_Name + 
'],' + CASE DATA_TYPE 
     WHEN 'int' THEN '0' 
     WHEN 'bigint' THEN '0' 
     WHEN 'tinyint' THEN '0' 
     WHEN 'uniqueidentifier' THEN '''0''' 
     WHEN 'varchar' THEN CHAR(39) + '-' + CHAR(39) 
     WHEN 'nvarchar' THEN CHAR(39) + '-' + CHAR(39) 
     WHEN 'date' THEN CHAR(39) + '1/1/1900' + CHAR(39) 
     WHEN 'datetime' THEN CHAR(39) + '1/1/1900 00:00:00' + CHAR(39) 
     ELSE '' 
     END + ') = IsNull(d.[' + Column_name + '],'+ 
     CASE DATA_TYPE 
     WHEN 'int' THEN '0' 
     WHEN 'bigint' THEN '0' 
     WHEN 'tinyint' THEN '0' 
     WHEN 'uniqueidentifier' THEN '''0''' 
     WHEN 'varchar' THEN CHAR(39) + '-' + CHAR(39) 
     WHEN 'nvarchar' THEN CHAR(39) + '-' + CHAR(39) 
     WHEN 'date' THEN CHAR(39) + '1/1/1900' + CHAR(39) 
     WHEN 'datetime' THEN CHAR(39) + '1/1/1900 00:00:00' + CHAR(39) 
     ELSE '' 
     END + ') then '''' 
else ' + quotename(Column_Name, char(39)) + ' + '',''' + ' end +' 
from information_schema.columns 
where table_name = 'Users' and column_name <>'rowguid' and column_name <>'modifieddate' 
--Define output parameter 
set @ParmDefinition = '@OutString varchar(max) OUTPUT' 
--Format sql 
set @sql = 'Select @OutString = ' 
+ Substring(@sql,1 , len(@sql) -1) + 
' From dbo.Users i ' --Will need to be updated for target schema 
+ ' inner join #tempTrigT d on 
i.id = d.id' --Will need to be updated for target schema 
--Execute sql and retrieve desired column list in output parameter 
exec sp_executesql @sql, @ParmDefinition, @OutString OUT 

Answer 1

下面的例子相應CASE可能看起來怎麼樣-however，不完成，你可能想擴展/重新設計一點：

Select @sql = @sql + 'Case when IsNull(i.[' + Column_Name + 
'],' + CASE DATA_TYPE 
     WHEN 'int' THEN '0' 
     WHEN 'bigint' THEN '0' 
     WHEN 'tinyint' THEN '0' 
     WHEN 'varchar' THEN CHAR(39) + '-' + CHAR(39) 
     WHEN 'nvarchar' THEN CHAR(39) + '-' + CHAR(39) 
     WHEN 'date' THEN CHAR(39) + '1900-01-01' + CHAR(39) 
     ELSE '' 
     END + ') = IsNull(d.[' + Column_name + '],'+ 
     CASE DATA_TYPE 
     WHEN 'int' THEN '0' 
     WHEN 'bigint' THEN '0' 
     WHEN 'tinyint' THEN '0' 
     WHEN 'varchar' THEN CHAR(39) + '-' + CHAR(39) 
     WHEN 'nvarchar' THEN CHAR(39) + '-' + CHAR(39) 
     WHEN 'date' THEN CHAR(39) + '1900-01-01' + CHAR(39) 
     ELSE '' 
     END + ') then '''' 
else ' + quotename(Column_Name, char(39)) + ' + '',''' + ' end +' 
from information_schema.columns