Quick & dirty:
Select Top 1000000
tblAssets.AssetID,
tblAssets.AssetName,
tsysAssetTypes.AssetTypename,
tsysAssetTypes.AssetTypeIcon10 As icon,
tblAssets.IPAddress,
tblAssets.Lastseen,
tblAssets.Lasttried,
(Select COUNT(*)
From tblUSBDevices
Where
tblUSBDevices.AssetID = tblAssets.AssetID
And tblUSBDevices.Name Like '%keyboard%'
And tblUSBDevices.Name Not Like '%Bluetooth%') As USBkeyboards
From
tblAssets
Inner Join tblAssetCustom On tblAssets.AssetID = tblAssetCustom.AssetID
Inner Join tsysAssetTypes On tsysAssetTypes.AssetType = tblAssets.Assettype
Where
tblAssetCustom.State = 1
AND (Select COUNT(*)
From tblUSBDevices
Where
tblUSBDevices.AssetID = tblAssets.AssetID
And tblUSBDevices.Name Like '%keyboard%'
And tblUSBDevices.Name Not Like '%Bluetooth%') > 1
(I spotted a few Bluetooth keyboards in my inventory when I tested and assumed those would be of no interest to you.)