Report to Show systems by Custom Field (Decommission Date)

[aplechaty]

I am pasting what i have that shows systems with the custom field Decommission date. It is custom field 15. What I need is to be able to run this report and it only generate Decommission dates within a certain date range say the past 3 months, or 6 months and so forth. Any help is greatly appreciated we need this for SOC purposes going forward.

Select Top 1000000 tblAssets.AssetID,
tblAssets.AssetName,
tblAssetCustom.Custom15 As [Decommission Date],
tblAssets.Domain,
tsysAssetTypes.AssetTypename As AssetType,
tblAssets.Username,
tblAssets.Userdomain,
Coalesce(tsysOS.Image, tsysAssetTypes.AssetTypeIcon10) As icon,
tblAssets.IPAddress,
tsysIPLocations.IPLocation,
tblAssetCustom.Manufacturer,
tblAssetCustom.Model,
Coalesce(tsysOS.OSname, tblMacOSInfo.SystemVersion, tblLinuxSystem.OSRelease)
As OS,
tblAssets.SP,
tblAssets.Lastseen,
tblAssets.Lasttried
From tblAssets
Inner Join tblAssetCustom On tblAssets.AssetID = tblAssetCustom.AssetID
Inner Join tsysAssetTypes On tsysAssetTypes.AssetType = tblAssets.Assettype
Inner Join tsysIPLocations On tsysIPLocations.LocationID =
tblAssets.LocationID
Inner Join tblState On tblState.State = tblAssetCustom.State
Left Join tsysOS On tsysOS.OScode = tblAssets.OScode
Left Join tblMacOSInfo On tblAssets.AssetID = tblMacOSInfo.AssetID
Left Join tblLinuxSystem On tblAssets.AssetID = tblLinuxSystem.AssetID
Where tblState.Statename = 'Active'
Order By tblAssets.IPNumeric,
tblAssets.AssetName