Is there a function like contents in mysql syntax?

I'm implementing an alarm window.

Implement Table A as an alarm history table.

I implemented table B as a history exclusion table

If [Remove all alarms], except for the history existing in table B,

I want to put all the remaining history of table A into table B, but I don't know how to organize the query.

Is there a function like contents?

INSERT INTO B Table
          (History key
          ,  User key
          ,  Input date
          )
     SELECT A table history key (maybe we need a function like contents here..)
          , #{A table user key}
          , , NOW()
       FROM A TABLE;