PROTECTED PROCEDURE VFP2SQL
  LPARAMETERS tvDataIn
  LOCAL lcRetVal

  do case
    case vartype(tvDataIn)='X'          &&null
        lcRetVal='NULL'
    case vartype(tvDataIn)='D'          &&date
      if empty(tvDataIn) or tvDataIn = {^1900/01/01}
        lcRetVal='NULL'
      else
        lcRetVal="'"+dtos(tvDataIn)+" 00:00:00'"
      endif
    case vartype(tvDataIn)='T'          &&time
      if empty(tvDataIn) or ttod(tvDataIn) ={^1900/01/01}
        lcRetVal='NULL'
      else
        lcRetVal="'"+dtos(ttod(tvDataIn))+' '+ttoc(tvDataIn, 2)+"'"
      endif
    case vartype(tvDataIn)='C'          &&character
      lcRetVal=C_SQUOTE+strtran(tvDataIn, C_SQUOTE, C_SQUOTE+C_SQUOTE)+C_SQUOTE