Querying an External Table with Kusto Query Language (KQL)

Correct Answer: A

After an external table is defined, the function external_table() should be used to refer to this table.

Any database reader or user can query an external table.

Option A is correct.

external_table() should be used to refer to the external table.

Option B is incorrect.

Access_table() is not the valid function.

Option C is incorrect.

There is no function like refer_table().

Option D is incorrect.

Any database reader or user can query an external table.

To know more about how to query data in Azure Data Lake using Azure Data Explorer, please visit the below-given link:

The correct function that a database user should use to refer to an external table named "ExtTable" in Azure Data Explorer using Kusto Query Language (KQL) is "external_table()".

External tables in Azure Data Explorer are tables that are created outside the Kusto engine, and their data is stored outside the Kusto cluster. These tables can be used in queries as if they were native Kusto tables. To query data from an external table, a user can use the external_table() function in KQL.

The external_table() function takes two arguments: the external table name and the external table schema. The external table name is the name of the external table in Azure Data Explorer, and the external table schema is the schema of the external table. The schema is optional and can be omitted if the external table schema is the same as the Kusto schema.

Therefore, to query data from an external table named "ExtTable" in Azure Data Explorer, the user should use the following KQL query:

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external_table("ExtTable") 

This query will return all the rows from the "ExtTable" external table.

Option D is not correct, as it is not necessary for only the table administrator to query the external table. Any user with appropriate permissions can query the external table.

Option B "access_table()" is not a valid function in KQL.

Option C "refer_table()" is not a valid function in KQL.