You're on the right track with LEFT JOIN. Just continue the thought... Try: SELECT A_data, B_data, C_data FROM A LEFT JOIN B ON A.A_ID = B.B_ID LEFT JOIN C ON A.A_ID = C.C_ID WHERE A.A_ID = 4;
> -----Original Message----- > From: sean peters [mailto:[EMAIL PROTECTED] > Sent: Wednesday, October 01, 2003 12:07 PM > To: [EMAIL PROTECTED] > Subject: How to write this query > > > I've run into a situation where i dont know how to best write > a query. For a > base example, consider these 3 tables: > > CREATE TABLE A ( > A_ID INT NOT NULL PRIMARY KEY, > A_data text > ); > > CREATE TABLE B ( > B_ID INT NOT NULL PRIMARY KEY, > A_ID INT NOT NULL, > B_data text > ); > > CREATE TABLE C ( > C_ID INT NOT NULL PRIMARY KEY, > A_ID INT NOT NULL, > C_data text > ); > > So ive been running a query like: > SELECT A_data, B_data, C_data FROM A, B, C > WHERE A.A_ID = B.B_ID > AND A.A_ID = C.C_ID > AND A.A_ID = 4; > > What i really want is to get the A_data from A, and if there > are cooresponding > records in B and/or C, get B_data and/or C_data, respectively. > > This works fine if there are cooresponding records in tables > B and C for each > record in A, but if not, this returns nothing. > > So, short of querying each table, i cant come up with a good > solution to my > problem. > > If there were only 2 tables, a LEFT JOIN would work fine, but > both B and C > want to be left joined to A, which i dont know how to do. > > thanks > sean peters > [EMAIL PROTECTED] > > > --- > mysql, query > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: > http://lists.mysql.com/mysql?> [EMAIL PROTECTED] > > -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
