错误报告-ORA-00908：缺少NULL关键字00908。00000-“缺少NULL关键字”

Question

我必须使用此脚本创建一个product_details表

CREATE TABLE product_details(
    product_detail_id NUMBER 
               --GENERATED BY DEFAULT AS IDENTITY START WITH 320 
               PRIMARY KEY,
    sizeof  VARCHAR( 40 ) NOT NULL,
    weights   VARCHAR( 40 ) NOT NULL,
    color   VARCHAR( 40 ) ,
    costof float NOT NULL,
    product_id  NUMBER ,--fk
    active NUMBER(1,0) NOT NULL,
    client_admin_id NUMBER ,--fk    
    --created_at TIMESTAMP WITH TIME ZONE NOT NULL , 
    config CLOB ,
    CONSTRAINT ensure_json CHECK (config IS JSON), 
     CONSTRAINT fk_pro_detail_products
      FOREIGN KEY(product_id)
      REFERENCES products(product_id)
      ON DELETE CASCADE,
     CONSTRAINT fk_pro_detail_client_admins
      FOREIGN KEY(client_admin_id)
      REFERENCES client_admins(client_admin_id) 
       ON DELETE CASCADE    

      );

我遇到错误，请寻求帮助