CREATE TABLE table_30273 ("Series no." FLOAT, "Season no." FLOAT, "Title" CLOB, "Directed by" CLOB, "Written by" CLOB, "Original air date" CLOB, "Production code" FLOAT)

how many people wrote the episode directed by rob schrab?
SELECT COUNT("Written by") FROM table_30273 WHERE "Directed by" = 'Rob Schrab'
SELECT COUNT("Written by") FROM "table_30273" WHERE "Directed by" = 'Rob Schrab'