message: Throw exception when multiple assignments to the same column are present in UPDATE clause (i.e. UPDATE table SET i=1, i=2)
diff: #include "duckdb/parser/expression/columnref_expression.hpp"
  #include "duckdb/storage/data_table.hpp"
  +#include <algorithm>
  +
  using namespace duckdb;
  using namespace std;
  @@ -101,6 +103,9 @@ unique_ptr<BoundSQLStatement> Binder::Bind(UpdateStatement &stmt) {
  throw BinderException("Referenced update column %s not found in table!", colname.c_str());
  }
  auto &column = table->GetColumn(colname);
  + if (std::find(result->column_ids.begin(), result->column_ids.end(), column.oid) != result->column_ids.end()) {
  + throw BinderException("Multiple assignments to same column \"%s\"", colname.c_str());
  + }
  result->column_ids.push_back(column.oid);
  if (expr->type == ExpressionType::VALUE_DEFAULT) {
  