Table: state_changes_2
Columns: state_class
vacator
reason_for_change
successor
date_of_successors_formal_installation

Question: Who was the successor for the state of Maine (2) ?
SQL: SELECT "successor" FROM state_changes_2 WHERE "state_class" = 'Maine (2)'

Question: What is the date of successors formal installation when the reason for change is resigned december 4, 1819?
SQL: SELECT "date_of_successors_formal_installation" FROM state_changes_2 WHERE "reason_for_change" = 'Resigned December 4, 1819'

Question: How many entries are shown for date of successors formal installation where successor is john w. walker (dr)?
SQL: SELECT COUNT("date_of_successors_formal_installation") FROM state_changes_2 WHERE "successor" = 'John W. Walker (DR)'

Question: Who was the successor for the state (class) of maine (2)?
SQL: SELECT "successor" FROM state_changes_2 WHERE "state_class" = 'Maine (2)'

Question: what is the state for reason for change is resigned may 15, 1820?
SQL: SELECT "state_class" FROM state_changes_2 WHERE "reason_for_change" = 'Resigned May 15, 1820'