问SQL Server导入向导将NULL视为文本字符串“NULL”

EN

update table1
set field1 = NULL
where field1 = 'null'

update table1
    set field1 = case when field1 = 'null' then Null else Field1 End
      , field2 = case when field2 = 'null' then Null else Field2 End
      , field3 = case when field3 = 'null' then Null else Field3 End

,,

NULL,NULL,

DECLARE @sql VARCHAR(MAX) = '';
SELECT @sql = CONCAT(@sql, '
    UPDATE [staging].[',[TABLE_NAME],']
    SET [',[COLUMN_NAME],'] = NULL
    WHERE [',[COLUMN_NAME],'] = ''NULL'';
    ')
FROM INFORMATION_SCHEMA.COLUMNS
WHERE [TABLE_SCHEMA] = 'staging' 
    AND [TABLE_NAME] IN ('MyTableName');
SELECT @sql;
EXEC(@sql);

INSERT INTO [dbo].[MyTableName] ([col1], [col2], [colN])
SELECT [col1], [col2], [colN]
FROM [staging].[MyTableName]