Get External DB List

Add-PSSnapin Microsoft.SharePoint.PowerShell

# Save in a variable the external lists you wish to report on

# in this example, the variable contains all external lists

# in a specific web application

$Lists = Get-SPWebApplication https://sitename| Select -ExpandProperty Sites | Select -ExpandProperty AllWebs | Select -ExpandProperty Lists | where {$_.hasexternaldatasource -eq $true}

# Save the expression to obtain the ECT name in a variable

$e=@{Expression={$_.DataSource.GetEntity().Name}}

# Output external lists grouped by ECT

$Lists | Sort $e | Format-Table Title, ParentWebUrl –Groupby $e