UpdateStatement <- WithClause? 'UPDATE' UpdateTarget UpdateSetClause FromClause? WhereClause? ReturningClause?

UpdateTarget <- (BaseTableName 'SET') / (BaseTableName UpdateAlias? 'SET')
UpdateAlias <- 'AS'? ColId
UpdateSetClause <- List(UpdateSetElement) / (Parens(List(ColumnName)) '=' Expression)
UpdateSetElement <- ColumnName '=' Expression