CREATE TABLE table_name_58 (nba_years_ VARCHAR2, a_ VARCHAR2, nationality VARCHAR2, previous_team VARCHAR2)

How many NBA years did the player from the United States who was previously on the los angeles lakers have?
SELECT nba_years_ AS "a_" FROM table_name_58 WHERE nationality = "united states" AND previous_team = "los angeles lakers"
SELECT "nba_years_" AS "a_" FROM "table_name_58" WHERE "los angeles lakers" = "previous_team" AND "nationality" = "united states"