How to self join and case when - mysql

Question

I have this monster query from a java application that I am reverse engineering.
`
SELECT
T.transferNumber,
T.TransferNumber,
T.BarrelsRequested - T.TotalBarrels br,
TrTy.TransferTypeName,
TrTa.SourceDest,
Ta.TankName,
SBP.SBPName,
T.Notes
FROM
RC.Transfers T,
RC.TransferTypes TrTy,
RC.TransferTank TrTa,
RC.Tanks Ta,
RC.ShipBargePipe SBP
WHERE
T.TransferTypeNumber = TrTy.TransferTypeNumber
AND T.TransferNumber = TrTa.TransferNumber
AND TrTa.TankNumber = Ta.TankNumber
AND T.SBPNumber = SBP.SBPNumber
AND T.StartStamp IS NOT NULL
AND T.EndStamp IS NULL
AND T.Void IS NULL
AND TrTy.TransferTypeName <> 'Truck'
UNION SELECT
T.transferNumber,
T.TransferNumber,
T.BarrelsRequested - T.TotalBarrels,
TrTy.TransferTypeName,
TrTa.SourceDest,
Ta.TankName,
'',
T.Notes
FROM
RC.Transfers T,
RC.TransferTypes TrTy,
RC.TransferTank TrTa,
RC.Tanks Ta
WHERE
T.TransferTypeNumber = TrTy.TransferTypeNumber
AND T.TransferNumber = TrTa.TransferNumber
AND TrTa.TankNumber = Ta.TankNumber
AND T.SBPNumber IS NULL
AND T.StartStamp IS NOT NULL
AND T.EndStamp IS NULL
AND T.Void IS NULL
AND TrTy.TransferTypeName <> 'Truck'
`
This returns a result set of:
But I really want:
Any help would be much appreciated. As mentioned in the picture, I want rows that have the same transfer number to show up on one line. I think I can achieve this using a self join, and
case when SourceDest = 's' AS 'FROM'
case when SourceDest = 'd' AS 'TO'
Also notice that when the type is Ship or Pipe, Then the from or To column becomes the SBPName depending on whether it is source or destination.
Thanks! Feel free to modify my question as you see fit too.
Edit*
Here is the java source code showing how they are grouping the rows together.
`
void updateRunning(Connection conn)
throws SQLException
{
Query q = new Query(conn);
this.jLabelRunningUpdate.setText("Reading");
this.jLabelRunningUpdate.setVisible(true);
q
.setQuery("SELECT T.transferNumber, T.TransferNumber, T.BarrelsRequested - T.TotalBarrels br, TrTy.TransferTypeName, TrTa.SourceDest, Ta.TankName, SBP.SBPName, T.Notes FROM RC.Transfers T, RC.TransferTypes TrTy, RC.TransferTank TrTa, RC.Tanks Ta, RC.ShipBargePipe SBP WHERE T.TransferTypeNumber = TrTy.TransferTypeNumber AND T.TransferNumber = TrTa.TransferNumber AND TrTa.TankNumber = Ta.TankNumber AND T.SBPNumber = SBP.SBPNumber AND T.StartStamp is not NULL AND T.EndStamp is NULL AND T.Void is NULL AND TrTy.TransferTypeName <> 'Truck' UNION SELECT T.transferNumber, T.TransferNumber, T.BarrelsRequested - T.TotalBarrels, TrTy.TransferTypeName, TrTa.SourceDest, Ta.TankName, '', T.Notes FROM RC.Transfers T, RC.TransferTypes TrTy, RC.TransferTank TrTa, RC.Tanks Ta WHERE T.TransferTypeNumber = TrTy.TransferTypeNumber AND T.TransferNumber = TrTa.TransferNumber AND TrTa.TankNumber = Ta.TankNumber AND T.SBPNumber is NULL AND T.StartStamp is not NULL AND T.EndStamp is NULL AND T.Void is NULL AND TrTy.TransferTypeName <> 'Truck'");
ResultSetCA transfers = q.execute(false);
this.jLabelRunningUpdate.setText("Updating");
String sourceTankList = "";
String destinationTankList = "";
ResultSetCA runningList = new ResultSetCA();
for (int count = 0; count < transfers.size(); count++)
{
sourceTankList = "";
destinationTankList = "";
String currentTNumber = transfers.getString(count, "transferNumber");
while ((count < transfers.size()) && (
currentTNumber.equals(transfers.getString(count, "transferNumber"))))
{
String sourceDest = transfers.getString(count, "sourceDest");
String tankName = transfers.getString(count, "tankName");
if (sourceDest.equals("s")) {
sourceTankList = sourceTankList + tankName + ", ";
} else {
destinationTankList = destinationTankList + tankName + ", ";
}
count++;
}
if (!sourceTankList.equals("")) {
sourceTankList = sourceTankList.substring(0, sourceTankList.length() - 2);
}
if (!destinationTankList.equals("")) {
destinationTankList =
destinationTankList.substring(0, destinationTankList.length() - 2);
}
count--;int lastCount = count;
String transferTypeName = transfers.getString(lastCount, "transferTypeName");
if (!transferTypeName.equals("Tank"))
{
String sbpName = transfers.getString(lastCount, "sbpName");
if (sourceTankList.equals("")) {
sourceTankList = sbpName;
} else {
destinationTankList = sbpName;
}
}
Number barrelsRemaining = transfers.getNumber(lastCount, "br");
Object BBLS;
Object BBLS;
if (barrelsRemaining == null) {
BBLS = "????";
} else {
BBLS = new Integer(barrelsRemaining.intValue());
}
Vector register = new Vector();
Integer transferNumber = transfers.getInteger(lastCount, "transferNumber");
String transferTName = transfers.getString(lastCount, "transferTypeName");
String notes = transfers.getString(lastCount, "notes");
register.add(transferNumber);
register.add(transferNumber);
register.add(BBLS);
register.add(transferTName);
register.add(sourceTankList);
register.add(destinationTankList);
register.add(notes);
runningList.add(register);
}
Object key = null;
if (this.jTableTransfersRunning.getSelectedRow() != -1) {
key = this.jTableTransfersRunning.getSelectedKey();
}
this.jTableTransfersRunning.fill(runningList);
if (runningList.size() > 0) {
if (key != null) {
this.jTableTransfersRunning.setSelectedKey(key);
}
}
this.jLabelRunningUpdate.setVisible(false);
}
`

Answer 1

EDITED
Give this a try:
SELECT
T.transferNumber,
T.BarrelsRequested - T.TotalBarrels AS `BBLs left`,
TrTy.TransferTypeName AS `Type`,
IF(TrTy.TransferTypeName = 'Tank',Ta.TankName,IFNULL(Ta.TankName,SBP.SBPName)) AS `From`,
IF(TrTy.TransferTypeName = 'Tank',Ta1.TankName,IFNULL(Ta1.TankName,SBP.SBPName)) AS `To`,
T.notes
FROM transfers T
JOIN transfertypes TrTy
ON T.TransferTypeNumber = TrTy.TransferTypeNumber
LEFT JOIN transfertank TrTa
ON T.TransferNumber = TrTa.TransferNumber
AND TrTa.SourceDest = 's'
LEFT JOIN tanks Ta
ON TrTa.TankNumber = Ta.TankNumber
LEFT JOIN transfertank TrTa1
ON T.TransferNumber = TrTa1.TransferNumber
AND TrTa1.SourceDest = 'd'
LEFT JOIN tanks Ta1
ON TrTa1.TankNumber = Ta1.TankNumber
LEFT JOIN shipbargepipe SBP
ON T.SBPNumber = SBP.SBPNumber
WHERE T.StartStamp IS NOT NULL
AND T.EndStamp IS NULL
AND T.Void IS NULL
AND TrTy.TransferTypeName <> 'Truck'
ORDER BY TRANSFERNUMBER

Answer 2

Join with this subquery instead of joining with TransferTank directly:
(SELECT t1.TransferNumber, t1.TankNumber, t1.SBPName AS From, t2.SBPName AS To
FROM TransferTank AS t1
JOIN TransferTank AS t2
ON t1.TransferNumber = t2.TransferNumber
AND t1.TankNumber = t2.TankNumber
WHERE t1.SourceDest = 's'
AND t2.SourceDesc = 'd') AS TrTa