PowerShell SQL Query Function

The function below can be used to a query to a database. The script returns any error as a result (2 lines).

function fnSQLCmd([string]$sInstance, [string]$sQuery, [string]$sDatabase) {
  # Register SQPPS Module...
  $oSQLPSModule = Get-Module | Where {$_.name -eq "SQLPS" }
  if ($oSQLPSModule.Count -eq 0) {
    Import-Module "SQLPS" -WarningAction SilentlyContinue
  }

  if ($sDatabase) {
    [string]$sQuery = "Invoke-SqlCmd -ServerInstance " + $sInstance + " -Database " + $sDatabase + " -QueryTimeout 30 -Query `"" + $sQuery + "`" ; if (`$? -eq `$false) { @{`"ERROR0`" = `$error[0]}; @{`"ERROR1`" = `$error[1]} }" 
  } else {
    [string]$sQuery = "Invoke-SqlCmd -ServerInstance " + $sInstance + " -QueryTimeout 30 -Query `"" + $sQuery + "`" ; if (`$? -eq `$false) { @{`"ERROR0`" = `$error[0]}; @{`"ERROR1`" = `$error[1]} }" 
  }
  return Invoke-Expression $sQuery
}