Why is the Tag Encoded Query Different from a Regular Reference Field in ServiceNow?

[nagaraju15]

I've noticed that the encoded query for tags in ServiceNow is different from the syntax used for regular reference fields. For example, in a regular reference field like assigned-to, the query is assigned-to = sysID, but for tags, it uses

sys-tags.(sysID) = sysID.

Could someone explain why the encoding for tags differs from regular reference fields? And How it will be executed in the backend ?

[Bert_c1]

In my instance, tag values are stored in the 'label' table, and instances of those used on other records are stored in the 'label_entry' table. Look at those table definitions to get an understanding of how they are related to records in the instance.  Use a query on sys_db_object table: "GOTOnameSTARTSWITHlabel"