Merge pull request #202260 from jovanpop-msft/patch-236

Updated differences between dedicated & serverless pool

Author: PRMerger13

articles/synapse-analytics/sql/develop-tables-external-tables.md

@@ -28,9 +28,10 @@ The key differences between Hadoop and native external tables are presented in t
 | Supported formats | Delimited/CSV, Parquet, ORC, Hive RC, and RC | Serverless SQL pool: Delimited/CSV, Parquet, and [Delta Lake](query-delta-lake-format.md)<br/>Dedicated SQL pool: Parquet (preview) |
 | [Folder partition elimination](#folder-partition-elimination) | No | Only for partitioned tables synchronized from Apache Spark pools in Synapse workspace to serverless SQL pools |
 | [File elimination](#file-elimination) (predicate pushdown) | No | Yes in serverless SQL pool. For the string pushdown, you need to use `Latin1_General_100_BIN2_UTF8` collation on the `VARCHAR` columns to enable pushdown. |
-| Custom format for location | No | Yes, using wildcards like `/year=*/month=*/day=*` |
-| Recursive folder scan | Yes | Only in serverless SQL pools when specified `/**` at the end of the location path |
+| Custom format for location | No | Yes, using wildcards like `/year=*/month=*/day=*`. In the serverless SQL pol you can also use recursive wildcards `/logs/**`.  |
+| Recursive folder scan | Yes | Yes. In serverless SQL pools must be specified `/**` at the end of the location path. In Dedicated pool the folders are alwasy scanned recursively. |
 | Storage authentication | Storage Access Key(SAK), AAD passthrough, Managed identity, Custom application Azure AD identity | [Shared Access Signature(SAS)](develop-storage-files-storage-access-control.md?tabs=shared-access-signature), [AAD passthrough](develop-storage-files-storage-access-control.md?tabs=user-identity), [Managed identity](develop-storage-files-storage-access-control.md?tabs=managed-identity), [Custom application Azure AD identity](develop-storage-files-storage-access-control.md?tabs=service-principal). |
+| Column mapping | Ordinal - the columns in the external table definition are mapped to the columns in the underlying Parquet files by position. | Serverless pool: by name. The columns in the external table definition are mapped to the columns in the underlying Parquet files by column name matching. <br/> Dedicated pool: ordinal matching. The columns in the external table definition are mapped to the columns in the underlying Parquet files by position.|
 
 > [!NOTE]
 > The native external tables are the recommended solution in the pools where they are generally available. If you need to access external data, always use the native tables in serverless pools. In dedicated pools, you should switch to the native tables for reading Parquet files once they are in GA. Use the Hadoop tables only if you need to access some types that are not supported in native external tables (for example - ORC, RC), or if the native version is not available.