如何在T-SQL中为变量插入转换变量？

Question

以下代码给出了一个错误(它是T-SQL存储过程的一部分):

-- Bulk insert data from the .csv file into the staging table.
DECLARE @CSVfile nvarchar(255);
SET @CSVfile = N'T:\x.csv';
BULK INSERT [dbo].[TStagingTable]
-- FROM N'T:\x.csv' -- This line works
FROM @CSVfile -- This line will not work
WITH
(
FIELDTERMINATOR = ',',
ROWTERMINATOR = '\n',
FIRSTROW = 2    
)

错误是:

Incorrect syntax near the keyword 'with'. 

如果我更换:

FROM @CSVfile

有:

FROM 'T:\x.csv'

......然后它很好用.

Answer 1

据我所知,from中只需要文字字符串.在这种情况下,您必须编写动态查询以使用批量插入

declare @q nvarchar(MAX);
set @q=
    'BULK INSERT [TStagingTable]
    FROM '+char(39)+@CSVfile+char(39)+'
    WITH
    (
    FIELDTERMINATOR = '','',
    ROWTERMINATOR = ''\n'',
    FIRSTROW = 1  
    )'
exec(@q)