运行 dynamic SQL with variable 时的单引号数量

Question

我真的很难整理 ' 我应该在以下 SQL 声明中的数量：

declare @sql varchar(max)
declare @LetterID varchar(max) = 'c01as1'
set @sql = 
'SELECT fltr.tency_seq_no FROM OPENQUERY(loopback, 
    ''SET FMTONLY OFF; EXEC BST.[LET].[LETTERBUILD] @LetterCode = 
        ''''\SVR-QL4APPLIVE\QLSHAREPOINT\LETTERS\DATAFILES\
            '''+@LetterID+'''
        .csv''''
    WITH RESULT SETS (tency_seq_no VARCHAR(255))''
) AS fltr'
exec (@sql)

当前错误：

Msg 102, Level 15, State 1, Line 3
Incorrect syntax near 'c01as1'

澄清一下，错误是指动态 SQL 中的 @LetterID 变量，而不是在声明参数时

打印@SQL

SELECT fltr.tency_seq_no 
FROM OPENQUERY(loopback, 'SET FMTONLY OFF; EXEC BST.[LET].[LETTERBUILD] @LetterCode = ''\SVR-QL4APPLIVE\QLSHAREPOINT\LETTERS\DATAFILES\'c01as1'.csv''
     WITH RESULT SETS (tency_seq_no VARCHAR(255));'
    ) AS fltr

如有任何帮助，我们将不胜感激！

Answer 1

我认为该错误与原始代码中不需要的换行符等有关。试试这个：

DECLARE @sql VARCHAR(MAX);
DECLARE @LetterID VARCHAR(MAX) = 'c01as1';

SET @sql = 'SELECT fltr.tency_seq_no FROM OPENQUERY(loopback, 
    ''SET FMTONLY OFF; EXEC BST.[LET].[LETTERBUILD] @LetterCode = ''''\SVR-QL4APPLIVE\QLSHAREPOINT\LETTERS\DATAFILES\'
           + @LetterID + '.csv''''
    WITH RESULT SETS (tency_seq_no VARCHAR(255))''
) AS fltr';

EXEC (@sql);

Answer 2

当我运行几个月前遇到这个困难时，我创建了一个函数，可以对动态 SQL 的报价执行加倍。这个标量函数可以执行此任务，而不是每次都手动搜索字符串以查找需要加倍的引号。这可以防止在执行未来修改时可能使脚本混乱，例如添加额外的变量，以及提高可读性。

函数如下：

CREATE FUNCTION dbo.fn_duplicateQuotes
    (@string varchar(max),
    @level int)
RETURNS varchar(max)
AS
BEGIN
    /*Doubles-up quotation marks for nested dynamic SQL
      level can be set greater than 1 to add additional doubled-up quotes
      for further nested dynamic SQL*/

    /*Double up quotes*/
        set @string = REPLACE(@string, '''', REPLICATE('''', (@level) * 2))

    /*Return Value*/
        return @string
END

动态SQL如下：

declare @SQL nvarchar(max)
declare @LetterID varchar(max) = 'c01as1'

set @SQL = 'SET FMTONLY OFF; EXEC BST.[LET].[LETTERBUILD] @LetterCode = 
              ''\SVR-QL4APPLIVE\QLSHAREPOINT\LETTERS\DATAFILES\' + @LetterID + '.csv''
             WITH RESULT SETS (tency_seq_no VARCHAR(255));'

set @SQL = 'SELECT fltr.tency_seq_no FROM OPENQUERY(loopback,
        ''' + dbo.fn_duplicateQuotes(@SQL, 1) + '''
        ) AS fltr'

print @SQL
exec (@SQL)

打印@SQL returns:

SELECT fltr.tency_seq_no FROM OPENQUERY(loopback,
        'SET FMTONLY OFF; EXEC BST.[LET].[LETTERBUILD] @LetterCode = 
              ''\SVR-QL4APPLIVE\QLSHAREPOINT\LETTERS\DATAFILES\c01as1.csv''
             WITH RESULT SETS (tency_seq_no VARCHAR(255));'
        ) AS fltr

运行 dynamic SQL with variable 时的单引号数量

Amount of single quotes when running dynamic SQL with variable

tsql

sql-server

dynamic-sql