Acumatica BQL Query with the same table more than once - acumatica

Question

I am trying to build a BQL query using the same table more than once. In my example below I am trying to use POVendorInventory as it relates to the default for the item and for each item warehouse (reason for the table listed twice in the query).
How do I do this in an Acumatica BQL Query. My current query is:
foreach (PXResult<INItemSite, InventoryItem, POVendorInventory, POVendorInventory> result in PXSelectJoin<INItemSite,
InnerJoin<InventoryItem, On<INItemSite.inventoryID, Equal<InventoryItem.inventoryID>>,
LeftJoin<POVendorInventory, On<InventoryItem.inventoryID, Equal<POVendorInventory.inventoryID>
, And<InventoryItem.preferredVendorID, Equal<POVendorInventory.vendorID>
, And<InventoryItem.preferredVendorLocationID, Equal<POVendorInventory.vendorLocationID>>>>,
LeftJoin<POVendorInventory, On<INItemSite.preferredVendorID, Equal<POVendorInventory.vendorID>,
And<INItemSite.inventoryID, Equal<POVendorInventory.inventoryID>>>>>>,
Where<InventoryItem.stkItem, Equal<boolTrue>>,
OrderBy<Asc<INItemSite.inventoryID, Asc<INItemSite.siteID>>>>.Select(graph))
{
var poVendorInventoryDefault = (POVendorInventory)result[2];
var poVendorInventorySite = (POVendorInventory)result[3];
}
The above results in the following error when the query is executed:
The correlation name 'POVendorInventory' is specified multiple times in a FROM clause.
The similar query in MS SQL is:
SELECT s.InventoryID ,
i.InventoryCD ,
s.SiteID ,
n.SiteCD ,
s.PreferredVendorID ,
s.PreferredVendorOverride ,
pd.VendorID ,
pd.AddLeadTimeDays ,
ps.VendorID ,
ps.AddLeadTimeDays
FROM dbo.INItemSite s
INNER JOIN dbo.InventoryItem i ON s.CompanyID = i.CompanyID
AND s.InventoryID = i.InventoryID
INNER JOIN dbo.INSite n ON s.CompanyID = n.CompanyID
AND s.SiteID = n.SiteID
LEFT JOIN dbo.POVendorInventory pd ON i.CompanyID = pd.CompanyID
AND i.InventoryID = pd.InventoryID
AND i.PreferredVendorID = pd.VendorID
AND i.PreferredVendorLocationID = pd.VendorLocationID
LEFT JOIN dbo.POVendorInventory ps ON s.CompanyID = ps.CompanyID
AND s.InventoryID = ps.InventoryID
AND s.PreferredVendorID = ps.VendorID
WHERE s.CompanyID = 2
AND i.StkItem = 1
ORDER BY s.InventoryID, s.SiteID
The following does not work either.
[Serializable]
public class POVendorInventoryTwo : POVendorInventory{}
PXResult<INItemSite, InventoryItem, POVendorInventoryTwo, POVendorInventory> result in PXSelectJoin<INItemSite,
InnerJoin<InventoryItem, On<INItemSite.inventoryID, Equal<InventoryItem.inventoryID>>,
LeftJoin<POVendorInventoryTwo, On<InventoryItem.inventoryID, Equal<POVendorInventoryTwo.inventoryID>
, And<InventoryItem.preferredVendorID, Equal<POVendorInventoryTwo.vendorID>
, And<InventoryItem.preferredVendorLocationID, Equal<POVendorInventoryTwo.vendorLocationID>>>>,
LeftJoin<POVendorInventory, On<INItemSite.preferredVendorID, Equal<POVendorInventory.vendorID>,
And<INItemSite.inventoryID, Equal<POVendorInventory.inventoryID>>>>>>,
Where<InventoryItem.stkItem, Equal<boolTrue>>,
OrderBy<Asc<INItemSite.inventoryID, Asc<INItemSite.siteID>>>>.Select(graph)
But as the answer mentions you need to use POVendorInventoryTwo for the second usage like so:
PXResult<INItemSite, InventoryItem, POVendorInventory, POVendorInventoryTwo> result in PXSelectJoin<INItemSite,
InnerJoin<InventoryItem, On<INItemSite.inventoryID, Equal<InventoryItem.inventoryID>>,
LeftJoin<POVendorInventory, On<InventoryItem.inventoryID, Equal<POVendorInventory.inventoryID>
, And<InventoryItem.preferredVendorID, Equal<POVendorInventory.vendorID>
, And<InventoryItem.preferredVendorLocationID, Equal<POVendorInventory.vendorLocationID>>>>,
LeftJoin<POVendorInventoryTwo, On<INItemSite.preferredVendorID, Equal<POVendorInventoryTwo.vendorID>,
And<INItemSite.inventoryID, Equal<POVendorInventoryTwo.inventoryID>>>>>>,
Where<InventoryItem.stkItem, Equal<boolTrue>>,
OrderBy<Asc<INItemSite.inventoryID, Asc<INItemSite.siteID>>>>.Select(graph)

Answer 1

What I've done in the past is subclass the DAC and query off that.
Something like this:
public class POVendorInventoryTwo : POVendorInventory
{}
Then in your BQL, use this subclassed version for the second value.