anchor.diff:  
   let private updateStmt =
       let setColumn =
  -        %% +.nameOrString
  +        %% +.name
           -- ws
           -- '='
           -- ws
  
positive.code:     -- +.[
              %% '(' -- ws -- +.parenthesized -- ')' -|> id
              %% kw "EXISTS" -- ws -- '(' -- ws -- +.selectStmt -- ')' -|> ExistsExpr
              %% +.qualifiedColumnName -|> ColumnNameExpr
              %% +.literal -|> LiteralExpr
              %% +.bindParameter -|> BindParameterExpr
              %% +.cast expr -|> CastExpr
  
negative.code: 
  let private asAlias =
      %% (zeroOrOne * kw "AS")
      -? +.name
      -|> id
  
  let private resultColumnCase =
  