I am trying to debug the following script:

DECLARE @lcField Char(40)
DECLARE @lcField2 Char(40)
DECLARE @lnNumero Integer
DECLARE @lnNumero2 Integer

WHILE EXISTS (SELECT @lnNumero=Numero,@lcField=Field,@lcField2=Field2 FROM Relation)
BEGIN
   PRINT 'Update Relation '+@lnNumero+'.'

   SELECT @lnNumero2=Numero FROM Field WHERE Field=@lcField

   UPDATE Relation SET NoField=@lnNumero2 WHERE Numero=@lnNumero

   SELECT @lnNumero2=Numero FROM Field WHERE Field=@lcField2

   UPDATE Relation SET NoField2=@lnNumero2 WHERE Numero=@lnNumero

END

On the WHILE EXISTS line, there is an error:

"Incorrect syntax near '='."

If I execute the SQL by itself, it works. So, it is a syntax problem with the use of WHILE EXISTS. Anyone would know what has to be adjusted?