(TOK_QUERY (TOK_FROM (TOK_TABREF (TOK_TABNAME src1))) (TOK_INSERT (TOK_DESTINATION (TOK_TAB (TOK_TABNAME 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