Question

I have two tables in MSSQL Server 2012 and would like to combine them into one new table. They are linked by the column messageID. The first table (Message) has

messageID
sender
date

The second table(recipientInfo) has

messageID
recipient

The main problem is that in Message the messageID is the primary key and thus unique. In recipientInfo the messageID is not unique (because one message can have multiple recipients). I’d like to have a new table with either

• One row per message, with recipients concatenated in one column
• Multiple rows per message, when there are multiple recipients (one recipient per row)

Answer 1

Maybe something like this (if you are using MSSQL 2005+):

CREATE TABLE NewTable
(
    messageID INT,
    sender VARCHAR(100),
    recipient VARCHAR(MAX),
    date DATETIME
)
INSERT INTO NewTable(messageID,sender,recipient,date)
SELECT
    [Message].messageID,
    [Message].sender,
    STUFF
    (
        (
            SELECT 
                ',' +recipient
            FROM
                recipientInfo
            WHERE
                recipientInfo.messageID=[Message].messageID
            FOR XML PATH('')
        )
    ,1,1,'') AS recipient,
    [Message].date
FROM
    [Message]