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

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