Issues with system.queryTagHistory

Good morning,
I am new in the ignition world and I am having some troubles with system.queryTagHistory function. When I use it to retrieve a tag which has a special character in the path, the query return null value.
I guess it is a problem with tag encoding conflict between ignition and my db server, which is by the way a sql server, but so far I haven’t manage to solve it.

the tag path I use is: plc_tv_1/Dati_Produzione/Velocità macchina m_min
while the string retrieved is: plc_tv_1/Dati_Produzione/Velocità macchina m_min

Thanks in advance for your help!

Yes, this almost certainly a database encoding issue that will have to be fixed in your database. You need to make sure the database is using UTF-8 or a Unicode encoding for your string/text columns. The best way to make this happen is to configure such an encoding as the database default, but it can be done table by table and column by column. After you set up the proper encoding, you’ll have to fix the contents, too. Possibly by re-configuring history.