14.29. SQL Server Connector

The SQL Server connector allows querying and creating tables in an external SQL Server database. This can be used to join data between different systems like SQL Server and Hive, or between two different SQL Server instances.


To configure the SQL Server connector, create a catalog properties file in etc/catalog named, for example, sqlserver.properties, to mount the SQL Server connector as the sqlserver catalog. Create the file with the following contents, replacing the connection properties as appropriate for your setup:


Multiple SQL Server Databases or Servers

The SQL Server connector can only access a single database within a SQL Server server. Thus, if you have multiple SQL Server databases, or want to connect to multiple instances of the SQL Server, you must configure multiple catalogs, one for each instance.

To add another catalog, simply add another properties file to etc/catalog with a different name (making sure it ends in .properties). For example, if you name the property file sales.properties, Presto will create a catalog named sales using the configured connector.

Querying SQL Server

The SQL Server connector provides access to all schemas visible to the specified user in the configured database. For the following examples, assume the SQL Server catalog is sqlserver.

You can see the available schemas by running SHOW SCHEMAS:


If you have a schema named web, you can view the tables in this schema by running SHOW TABLES:

SHOW TABLES FROM sqlserver.web;

You can see a list of the columns in the clicks table in the web database using either of the following:

DESCRIBE sqlserver.web.clicks;
SHOW COLUMNS FROM sqlserver.web.clicks;

Finally, you can query the clicks table in the web schema:

SELECT * FROM sqlserver.web.clicks;

If you used a different name for your catalog properties file, use that catalog name instead of sqlserver in the above examples.

User Impersonation

SQL Server connector supports user impersonation. Please see User Impersonation for more details.

User impersonation can be turned with:


User impersonation in SQL Server connector is based on EXECUTE AS USER. For more details please visit: docs.microsoft.com.

Table Statistics

SQL Server connector supports table and column statistics. The statistics are collected by SQL Server Database and retrieved by the connector. Currently, the connector can use information stored in single-column statistics. SQL Server Database can automatically create column statistics for certain columns. If column statistics were not created automatically for a certain column, you can create them by executing the following statement in SQL Server Database.

CREATE STATISTICS my_statistics_name ON table_schema.table_name (column_name);

SQL Server Database routinely updates the statistics. In some cases, you may want to force statistics update (e.g. after defining new column statistics or after changing data in the table). You can do that by executing the following statement in SQL Server Database.

UPDATE STATISTICS table_schema.table_name;

Please refer to SQL Server documentation for information about options, limitations and additional considerations.

The table and column statistics can be viewed in Presto using SHOW STATS and are used for Cost-Based Optimizations.

Table Statistics Configuration Properties

Property Name Description Default
statistics.enabled Enables table and column statistics. true
statistics.cache-ttl Duration for which table and column statistics are cached. 0s
statistics.cache-missing Cache the fact that table statistics were not available. false

SQL Server Connector Limitations

Presto supports connecting to SQL Server 2016, SQL Server 2014, SQL Server 2012 and Azure SQL Database.

Presto supports the following SQL Server data types. The following table shows the mappings between SQL Server and Presto data types.

SQL Server Type Presto Type
bigint bigint
smallint smallint
int integer
float double
char(n) char(n)
varchar(n) varchar(n)
date date

Complete list of SQL Server data types.

The following SQL statements are not yet supported: