How many where killed under Major-General Jean Victor de Constant Rebecque's command?
CREATE TABLE "table1_11793221_2" (
  "unit" text,
  "commander" text,
  "complement" text,
  "killed" text,
  "wounded" text,
  "missing" text
);
SELECT "killed" FROM "table1_11793221_2" WHERE "commander"='Major-General Jean Victor de Constant Rebecque';