It looks like there's already an OUI table in the database, tSysMacVendor. The
IEEE list changes over time, so not all of yours will necessarily be in there right now, but you should be able to append new entries to the table.
I'm skimming the tables to see if there's a colon-stripped copy of the MAC stored someplace but not having any luck. Assuming that it's not there to be found, adding a link to the tSysMacVendor table should do the trick for you.
Select Top 1000000
tblAssets.AssetID,
tblAssets.AssetName,
tsysAssetTypes.AssetTypename,
tsysAssetTypes.AssetTypeIcon10 As icon,
tblAssets.IPAddress,
tblAssets.Lastseen,
tblAssets.Lasttried,
tblAssets.Mac,
tsysMacVendor.Vendor
From
tblAssets
Inner Join tblAssetCustom On tblAssets.AssetID = tblAssetCustom.AssetID
Inner Join tsysAssetTypes On tsysAssetTypes.AssetType = tblAssets.Assettype
Inner Join tsysMacVendor On tsysMacVendor.MAC = Replace(Left(tblAssets.Mac, 8), ':', '')
Where
tblAssetCustom.State = 1
AND tblAssets.Mac <> ''
AND Replace(Left(tblAssets.Mac, 8), ':', '') In ('00000A','000023','00002B','0000BC','000105','00010D','000123','000158','0001C3','0001EE','00022C','000248','0002A2','0002A3','0002D3','000305','000317','00032C','000358','00037B','00038D','0003AA','0003AD','000417','000463','0004D7','00054B','000594','0005DA','00063D','000660','000677','000746','000768','0007A6','0007BE','000808','00089B','0008CC','00097E','000991','0009F5','000A44','000A66','000AA9','000ADC','000AED','000B17','000B29','000B2D','000BCB','000BF3','000C02','000C1A','000C62','000C87','000CDE','000D1E','000D81','000D98','000DAB','000E13','000EC1','000ECF','000EF0','000F18','000F67','000F69','000F73','000F9C','000F9E','001025','001048','0010C3','001182','0011FC','00120A','00121F','00124F','001293','0012A8','0012C2','0012ED','001324','001345','001384','001386','001411','001415','0014F7','0014FF','001524','00154E','0015A6','0015BA','0015DD','0015FC','00165F','001677','0016BD','002004','002025','002034','00203D','002096','00209D','0020B5','003011','003056','003097','0030A0','0030DE','00401A','0040AE','0040C3','0050A0','0050CB','0050DB','0050FF','006041','0060B2','0060E5','008074','008094','0080A3','00904F','009068','0090DF','0090E8','00A03D','00A045','00A0ED','00C04E','00C0AF','00C0CB','00D024','00D026','00D027','00D0AF','00E067','00E07E','00E090','00E0A1','00E0C4','00E0E4','080017','080070','1000E8')