dblink_write implement [FEAT MERGE]

Co-authored-by: zzg19950727 <1071026277@qq.com>
Co-authored-by: xianyu-w <707512433@qq.com>

src/sql/ob_merge_stmt_printer.cpp

@@ -45,6 +45,8 @@ int ObMergeStmtPrinter::print()
     ret = OB_ERR_UNEXPECTED;
     LOG_WARN("stmt_ is NULL or buf_ is NULL or pos_ is NULL", K(ret),
              K(stmt_), K(buf_), K(pos_));
+  } else if (print_params_.print_with_cte_ && OB_FAIL(print_cte_define())) {
+    LOG_WARN("failed to print cte", K(ret));
   } else {
     const ObMergeStmt *merge_stmt = static_cast<const ObMergeStmt *>(stmt_);
     const TableItem *target_table = NULL;