如何显示SQL "PRINT"命令

本文关键字：quot PRINT 命令 SQL 何显示 显示 | 更新日期: 2023-09-27 18:19:06

我有一个SQL过程，总是返回"PRINT"命令，我想提取这个"PRINT"命令的输出，即c#中的过程，我怎么能做到这一点?这里是PROCEDURE

ALTER PROC ResultsPoll
@pollid INT 
AS
DECLARE @count1 INT 
DECLARE @count2 INT 
DECLARE @count3 INT 
DECLARE @count4 INT 
DECLARE @count5 INT 
DECLARE @test VARCHAR(MAX)
DECLARE @value VARCHAR(MAX)
SELECT @count1 = COUNT(mem_id) FROM Students_answer_Polls INNER JOIN Polls ON Polls.poll_id = Students_answer_Polls.poll_id
WHERE Students_answer_Polls.poll_id = @pollid AND Students_answer_Polls.answer = Polls.a1
SELECT @count2 = COUNT(mem_id) FROM Students_answer_Polls INNER JOIN Polls ON Polls.poll_id = Students_answer_Polls.poll_id
WHERE Students_answer_Polls.poll_id = @pollid AND Students_answer_Polls.answer = Polls.a2
SELECT @count3 = COUNT(mem_id) FROM Students_answer_Polls INNER JOIN Polls ON Polls.poll_id = Students_answer_Polls.poll_id
WHERE Students_answer_Polls.poll_id = @pollid AND Students_answer_Polls.answer = Polls.a3
SELECT @count4 = COUNT(mem_id) FROM Students_answer_Polls INNER JOIN Polls ON Polls.poll_id = Students_answer_Polls.poll_id
WHERE Students_answer_Polls.poll_id = @pollid AND Students_answer_Polls.answer = Polls.a4
SELECT @count5 = COUNT(mem_id) FROM Students_answer_Polls INNER JOIN Polls ON Polls.poll_id = Students_answer_Polls.poll_id
WHERE Students_answer_Polls.poll_id = @pollid AND Students_answer_Polls.answer = Polls.a5
SELECT @test=Polls.a1 FROM Polls WHERE poll_id = @pollid
IF(@test IS NOT NULL)
BEGIN
PRINT ('Number of students who chose '+@test+' is:'+' '+CAST (@count1 AS VARCHAR(MAX)))
END
SELECT @test=Polls.a2 FROM Polls WHERE poll_id = @pollid
IF(@test IS NOT NULL)
BEGIN
PRINT ('Number of students who chose '+@test+' is:'+' '+CAST (@count2 AS VARCHAR(MAX)))
END
SELECT @test=Polls.a3 FROM Polls WHERE poll_id = @pollid
IF(@test IS NOT NULL)
BEGIN
PRINT ('Number of students who chose '+@test+' is:'+' '+CAST (@count3 AS VARCHAR(MAX)))
END
SELECT @test=Polls.a4 FROM Polls WHERE poll_id = @pollid
IF(@test IS NOT NULL)
BEGIN
PRINT ('Number of students who chose '+@test+' is:'+' '+CAST (@count4 AS VARCHAR(MAX)))
END
SELECT @test=Polls.a5 FROM Polls WHERE poll_id = @pollid
IF(@test IS NOT NULL)
BEGIN
PRINT ('Number of students who chose '+@test+' is:'+' '+CAST (@count5 AS VARCHAR(MAX)))
END

如何显示SQL "PRINT"命令

您需要订阅SqlConnection.InfoMessage事件。

MSDN有一些示例代码在这里

正确的方法是将值记录在输出参数中，然后在存储过程中打印输出参数值。

例如:

ALTER PROC ResultsPoll
@pollid INT ,
@message varchar(max) OUTPUT
AS
SET @message = ''
...
IF(@test IS NOT NULL)
BEGIN
SET @message = 'Number of students who chose '+@test+' is:'+' '+CAST (@count1 AS VARCHAR(MAX))
END
...
PRINT(@message)

然后，在代码中检索输出参数的值。

上述建议仅在返回单个状态或错误消息时才有效。仔细检查存储过程后，我意识到这个存储过程并非如此，因为print语句用于向调用应用程序返回数据。

现在我明白了这一点，我建议，如果可能的话，将存储过程重写如下: 
ALTER PROC ResultsPoll
@pollid INT 
AS
SELECT result = 'Number of students who chose ' + MAX(Polls.a1) + ' is: ' + CAST(COUNT(1) AS NVARCHAR(MAX)) 
  FROM Students_answer_Polls INNER JOIN Polls ON Polls.poll_id = Students_answer_Polls.poll_id
 WHERE Students_answer_Polls.poll_id = @pollid AND Students_answer_Polls.answer = Polls.a1
UNION
SELECT result = 'Number of students who chose ' + MAX(Polls.a2) + ' is: ' + CAST(COUNT(1) AS NVARCHAR(MAX)) 
  FROM Students_answer_Polls INNER JOIN Polls ON Polls.poll_id = Students_answer_Polls.poll_id
 WHERE Students_answer_Polls.poll_id = @pollid AND Students_answer_Polls.answer = Polls.a2
UNION
SELECT result = 'Number of students who chose ' + MAX(Polls.a3) + ' is: ' + CAST(COUNT(1) AS NVARCHAR(MAX)) 
  FROM Students_answer_Polls INNER JOIN Polls ON Polls.poll_id = Students_answer_Polls.poll_id
 WHERE Students_answer_Polls.poll_id = @pollid AND Students_answer_Polls.answer = Polls.a3
UNION
SELECT result = 'Number of students who chose ' + MAX(Polls.a4) + ' is: ' + CAST(COUNT(1) AS NVARCHAR(MAX)) 
  FROM Students_answer_Polls INNER JOIN Polls ON Polls.poll_id = Students_answer_Polls.poll_id
 WHERE Students_answer_Polls.poll_id = @pollid AND Students_answer_Polls.answer = Polls.a4
UNION
SELECT result = 'Number of students who chose ' + MAX(Polls.a5) + ' is: ' + CAST(COUNT(1) AS NVARCHAR(MAX)) 
  FROM Students_answer_Polls INNER JOIN Polls ON Polls.poll_id = Students_answer_Polls.poll_id
 WHERE Students_answer_Polls.poll_id = @pollid AND Students_answer_Polls.answer = Polls.a5

这样，您就可以处理返回的行，这些行将包含一个名为result的列。

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