List files in a folder by extension

Lists only files whose names match the given extensions (e.g. .csv, .txt, .dat). Use the Filter parameter with a JSONPath expression that filters by .tag and name pattern.

Standard SQL query example

This is the base query accepted by the connector. To execute it in SQL Server, you have to pass it to the Data Gateway via a Linked Server. See how to accomplish this using the examples below.

SELECT *
FROM list_files
WITH (Path='/myfolder'
     ,Filter='$.entries[?(@[''.tag'']==''file'' && @name=~/(\.csv|\.txt|\.dat)$/)]')

Using OPENQUERY in SQL Server

SELECT * FROM OPENQUERY([LS_TO_DROPBOX_IN_GATEWAY], 'SELECT *
FROM list_files
WITH (Path=''/myfolder''
     ,Filter=''$.entries[?(@[''''.tag'''']==''''file'''' && @name=~/(\.csv|\.txt|\.dat)$/)]'')')

Using EXEC in SQL Server (handling larger SQL text)

The major drawback of OPENQUERY is its inability to incorporate variables within SQL statements. This often leads to the use of cumbersome dynamic SQL (with numerous ticks and escape characters).

Fortunately, starting with SQL 2005 and onwards, you can utilize the EXEC (your_sql) AT [LS_TO_DROPBOX_IN_GATEWAY] syntax.

DECLARE @MyQuery NVARCHAR(MAX) = 'SELECT *
FROM list_files
WITH (Path=''/myfolder''
     ,Filter=''$.entries[?(@[''''.tag'''']==''''file'''' && @name=~/(\.csv|\.txt|\.dat)$/)]'')'
EXEC (@MyQuery) AT [LS_TO_DROPBOX_IN_GATEWAY]