private String buildUpdateConnection(String[] fieldNames, String[] uniqueKeyFields) {
        List<String> uniqueKeyList = Arrays.asList(uniqueKeyFields);
        return Arrays
                .stream(fieldNames)
                .filter(col -> !uniqueKeyList.contains(col))
                .map(col -> quoteIdentifier("T1") + "." + quoteIdentifier(col)
                        + " =ISNULL(" + quoteIdentifier("T2") + "." + quoteIdentifier(col)
                        + "," + quoteIdentifier("T1") + "." + quoteIdentifier(col) + ")")
                .collect(Collectors.joining(","));
    }
SqlServer merge data.
https://docs.microsoft.com/en-us/sql/t-sql/statements/merge-transact-sql?view=sql-server-ver15
inlong-sort/sort-flink/sort-flink-v1.13/sort-connectors/jdbc/src/main/java/org/apache/inlong/sort/jdbc/dialect/SqlServerDialect.java