Question

I’m pulling email address records from a table in SQL Server 2005, and want to build a single string to use as the @recipients list with sp_send_dbmail. The table has a field called EmailAddress and there are 10 records in the table.

I’m doing this:

DECLARE @email VARCHAR(MAX) SELECT     @email = ISNULL(@email + '; ', '') + EmailAddress FROM     accounts 

Now @email has a semi-delimited list of 10 email address from the accounts table.

My questions is why/how does this work? Why doesn’t @email only have the last email address in the table?

Answer 1

Because for each row you concatentate the current value of @email with the next result in EmailAddress. String concatenation is just like calling a function, in that it must evaluate the result for each row in sequence.