CREATE TABLE table_203_404 (id DECIMAL, "pennant\ number" TEXT, "name" TEXT, "builder" TEXT, "laid down" TEXT, "launched" TEXT, "completed" TEXT, "fate" TEXT)

total number of j class ships completed .
SELECT COUNT(*) FROM table_203_404 WHERE NOT "completed" IS NULL
SELECT COUNT(*) FROM "table_203_404" WHERE NOT "completed" IS NULL