我的一个数据库中有一个表格，它是一个电子邮件队列。发送到特定地址的电子邮件会累积到一封电子邮件中，这是由存储过程完成的。在存储过程中，我有一个表变量，用于构建电子邮件的累积正文，然后循环发送每封电子邮件。在我的表 var 中，我的 body 列定义为VARCHAR(MAX)，因为当前可能为给定的电子邮件地址累积了任意数量的电子邮件。似乎即使我的列被定义为VARCHAR(MAX)它的行为就像它一样VARCHAR(4000)并且正在截断进入它的数据，尽管它没有抛出任何异常，但它只是在 4000 个字符后默默地停止连接任何更多数据。
MERGE 语句将累积的电子邮件正文构建到@EMAILS.BODY 中，这是将自身截断为4000 个字符的字段。
编辑
我更新了我的 MERGE 语句，试图将整个分配的字符串转换为 VARCHAR(MAX)，但它仍然默默地将自己截断为 4000 个字符......这是我的新 MERGE：
MERGE @EMAILS AS DST
USING (SELECT * FROM @ROWS WHERE ROWID = @CURRID) AS SRC
ON SRC.ADDRESS = DST.ADDRESS
WHEN MATCHED THEN
UPDATE SET
DST.ALLIDS = DST.ALLIDS + ', ' + CONVERT(VARCHAR,ROWID),
DST.BODY = DST.BODY +
CONVERT(VARCHAR(MAX),
'<i>'+CONVERT(VARCHAR,SRC.DATED,101)+
' '+CONVERT(VARCHAR,SRC.DATED,8)+
':</i> <b>'+SRC.SUBJECT+'</b>'+CHAR(13)+
SRC.BODY+' (Message ID '+
CONVERT(VARCHAR,SRC.ROWID)+')'+
CHAR(13)+CHAR(13)
)
WHEN NOT MATCHED BY TARGET THEN
INSERT (ADDRESS, ALLIDS, BODY) VALUES (
SRC.ADDRESS,
CONVERT(VARCHAR,ROWID),
CONVERT(VARCHAR(MAX),
'<i>'+CONVERT(VARCHAR,SRC.DATED,101)+
' '+CONVERT(VARCHAR,SRC.DATED,8)+
':</i> <b>'+SRC.SUBJECT+'</b>'+CHAR(13)+
SRC.BODY+' (Message ID '+CONVERT(VARCHAR,SRC.ROWID)+')'
+CHAR(13)+CHAR(13)
)
);
结束编辑
下面是我的sproc的代码...
ALTER PROCEDURE [system].[SendAccumulatedEmails]
AS
BEGIN
SET NOCOUNT ON;
DECLARE @SENTS BIGINT = 0;
DECLARE @ROWS TABLE (
ROWID ROWID,
DATED DATETIME,
ADDRESS NAME,
SUBJECT VARCHAR(1000),
BODY VARCHAR(MAX)
)
INSERT INTO @ROWS SELECT ROWID, DATED, ADDRESS, SUBJECT, BODY
FROM system.EMAILQUEUE
WHERE ACCUMULATE = 1 AND SENT IS NULL
ORDER BY ADDRESS, DATED
DECLARE @EMAILS TABLE (
ADDRESS NAME,
ALLIDS VARCHAR(1000),
BODY VARCHAR(MAX)
)
DECLARE @PRVRID ROWID = NULL, @CURRID ROWID = NULL
SELECT @CURRID = MIN(ROWID) FROM @ROWS
WHILE @CURRID IS NOT NULL BEGIN
MERGE @EMAILS AS DST
USING (SELECT * FROM @ROWS WHERE ROWID = @CURRID) AS SRC
ON SRC.ADDRESS = DST.ADDRESS
WHEN MATCHED THEN
UPDATE SET
DST.ALLIDS = DST.ALLIDS + ', ' + CONVERT(VARCHAR,ROWID),
DST.BODY = DST.BODY + '<i>'+CONVERT(VARCHAR,SRC.DATED,101)+' '
+CONVERT(VARCHAR,SRC.DATED,8)
+':</i> <b>'+SRC.SUBJECT+'</b>'+CHAR(13)+SRC.BODY
+' (Message ID '+CONVERT(VARCHAR,SRC.ROWID)+')'
+CHAR(13)+CHAR(13)
WHEN NOT MATCHED BY TARGET THEN
INSERT (ADDRESS, ALLIDS, BODY) VALUES (
SRC.ADDRESS,
CONVERT(VARCHAR,ROWID),
'<i>'+CONVERT(VARCHAR,SRC.DATED,101)+' '
+CONVERT(VARCHAR,SRC.DATED,8)+':</i> <b>'
+SRC.SUBJECT+'</b>'+CHAR(13)+SRC.BODY
+' (Message ID '+CONVERT(VARCHAR,SRC.ROWID)+')'
+CHAR(13)+CHAR(13));
SELECT @PRVRID = @CURRID, @CURRID = NULL
SELECT @CURRID = MIN(ROWID) FROM @ROWS WHERE ROWID > @PRVRID
END
DECLARE @MAILFROM VARCHAR(100) = system.getOption('MAILFROM'),
DECLARE @SMTPHST VARCHAR(100) = system.getOption('SMTPSERVER'),
DECLARE @SMTPUSR VARCHAR(100) = system.getOption('SMTPUSER'),
DECLARE @SMTPPWD VARCHAR(100) = system.getOption('SMTPPASS')
DECLARE @ADDRESS NAME, @BODY VARCHAR(MAX), @ADDL VARCHAR(MAX)
DECLARE @SUBJECT VARCHAR(1000) = 'Accumulated Emails from LIJSL'
DECLARE @PRVID NAME = NULL, @CURID NAME = NULL
SELECT @CURID = MIN(ADDRESS) FROM @EMAILS
WHILE @CURID IS NOT NULL BEGIN
SELECT @ADDRESS = ADDRESS, @BODY = BODY
FROM @EMAILS WHERE ADDRESS = @CURID
SELECT @BODY = @BODY + 'This is an automated message sent from an unmonitored mailbox.'+CHAR(13)+'Do not reply to this message; your message will not be read.'
SELECT @BODY =
'<style type="text/css">
* {font-family: Tahoma, Arial, Verdana;}
p {margin-top: 10px; padding-top: 10px; border-top: single 1px dimgray;}
p:first-child {margin-top: 10px; padding-top: 0px; border-top: none 0px transparent;}
</style>'
+ @BODY
exec system.LogIt @SUBJECT, @BODY
BEGIN TRY
exec system.SendMail @SMTPHST, @SMTPUSR, @SMTPPWD, @MAILFROM,
@ADDRESS, NULL, NULL, @SUBJECT, @BODY, 1
END TRY
BEGIN CATCH
DECLARE @EMSG NVARCHAR(2048) = 'system.EMAILQUEUE.AI:'+ERROR_MESSAGE()
SELECT @ADDL = 'TO:'+@ADDRESS+CHAR(13)+'SUBJECT:'+@SUBJECT+CHAR(13)+'BODY:'+@BODY
exec system.LogIt @EMSG,@ADDL
END CATCH
SELECT @PRVID = @CURID, @CURID = NULL
SELECT @CURID = MIN(ADDRESS) FROM @EMAILS WHERE ADDRESS > @PRVID
END
UPDATE system.EMAILQUEUE SET SENT = getdate()
FROM system.EMAILQUEUE E, @ROWS R WHERE E.ROWID = R.ROWID
END