(TOK_QUERY (TOK_FROM (TOK_TABREF src1)) (TOK_INSERT (TOK_DESTINATION (TOK_TAB dest1)) (TOK_SELECT (TOK_SELEXPR (. (TOK_TABLE_OR_COL src1) key)) (TOK_SELEXPR (. (TOK_TABLE_OR_COL src1) value))) (TOK_WHERE (TOK_FUNCTION TOK_ISNULL (. (TOK_TABLE_OR_COL src1) key))))) null