ERROR: syntax error at or near "INDEX"

[Palin Lertpoonwasin]

Hi guys,

I have written a script in Postgresql to create a table. Now I have a problem with UNIQUE INDEX. So I went to find information on the website and found that INDEX is not suitable for the large amount of data that has NULL values.  From the attached photo, I copied the script from a website that I want to retrieve the data for synchronization to create a table. Now, I'm not sure if it's the postgresql that doesn't support or if I need to modify it.

thank you

Reference

https://help.pi-datametrics.com/en/articles/4560158-pi-sync