How to search for some particular SQL commands in TNS proprietary protocol with tshark.

Issue

There is a need to check if some particular SQL commands can be seen in captured network dump.
But the tshark shows TNS protocol.

Transparent Network Substrate (TNS), a proprietary Oracle computer-networking technology, supports homogeneous peer-to-peer connectivity on top of other networking technologies such as TCP/IP, SDP and named pipes. TNS operates mainly for connection to Oracle databases.

$tshark -r some_file.pcap tcp.stream eq 1
...
6  04:10:19.804101 xxx.xxx.xxx.xxx→yyy.yyy.yyy.yyy TNS 89 38108 1521 Request, Data (6), Piggy back function follow
7  04:10:19.804342 xxx.xxx.xxx.xxx→yyy.yyy.yyy.yyy TNS 84 1521 38108 Response, Data (6), Function Complete
...
9  04:10:19.807417 xxx.xxx.xxx.xxx→yyy.yyy.yyy.yyy TNS 254 38108 1521 Request, Data (6), User OCI Functions
10 04:10:19.807763 xxx.xxx.xxx.xxx→yyy.yyy.yyy.yyy TNS 253 1521 38108 Response, Data (6), Describe Information
...

There is a need to search in the capture file for presence of particular SQL commands like SELECT, MERGE, INSERT etc.