Per current book issue calculate days elapsed since

For each current book issue, calculate the days elapsed since issue and flag it as 'OVERDUE' if it exceeds the member's quota duration, otherwise 'OK'.

---

Database schema

CREATE TABLE "public"."staff" (
    "staff_fname" varchar(80) NOT NULL,
    "staff_lname" varchar(80) NOT NULL,
    "id" varchar(20) NOT NULL,
    "gender" varchar(1) NOT NULL,
    "mobile_no" numeric(10,0) NOT NULL,
    "doj" date NOT NULL,
    PRIMARY KEY ("id")
);

CREATE TABLE "public"."book_catalogue" (
    "isbn_no" varchar(50) NOT NULL,
    "title" varchar(256) NOT NULL,
    "publisher" varchar(80) NOT NULL,
    "year" int4 NOT NULL,
    PRIMARY KEY ("isbn_no")
);

CREATE TABLE "public"."book_authors" (
    "isbn_no" varchar(13) NOT NULL,
    "author_fname" varchar(80) NOT NULL,
    "author_lname" varchar(80) NOT NULL,
    PRIMARY KEY ("isbn_no","author_fname","author_lname")
);

CREATE TABLE "public"."book_copies" (
    "isbn_no" varchar(13) NOT NULL,
    "accession_no" varchar(20) NOT NULL,
    PRIMARY KEY ("accession_no")
);

CREATE TABLE "public"."members" (
    "member_no" varchar(20) NOT NULL,
    "member_class" varchar(20) NOT NULL,
    "member_type" varchar(2) NOT NULL,
    "roll_no" varchar(20),
    "id" varchar(20),
    PRIMARY KEY ("member_no")
);

CREATE TABLE "public"."book_issue" (
    "member_no" varchar(20) NOT NULL,
    "accession_no" varchar(20) NOT NULL,
    "doi" date NOT NULL,
    PRIMARY KEY ("member_no","accession_no")
);

CREATE TABLE "public"."departments" (
    "department_code" varchar(80) NOT NULL,
    "department_name" varchar(80),
    "department_building" varchar(80),
    PRIMARY KEY ("department_code")
);

CREATE TABLE "public"."faculty" (
    "faculty_fname" varchar(80) NOT NULL,
    "faculty_lname" varchar(80) NOT NULL,
    "id" varchar(20) NOT NULL,
    "department_code" varchar(80) NOT NULL,
    "gender" varchar(1) NOT NULL,
    "mobile_no" numeric(10,0) NOT NULL,
    "doj" date NOT NULL,
    PRIMARY KEY ("id")
);

CREATE TABLE "public"."students" (
    "student_fname" varchar(80) NOT NULL,
    "student_lname" varchar(80) NOT NULL,
    "roll_no" varchar(20) NOT NULL,
    "department_code" varchar(80) NOT NULL,
    "gender" varchar(1) NOT NULL,
    "mobile_no" numeric(10,0) NOT NULL,
    "dob" date NOT NULL,
    "degree" varchar(80) NOT NULL,
    PRIMARY KEY ("roll_no")
);

CREATE TABLE "public"."quota" (
    "member_type" varchar(2) NOT NULL,
    "max_books" int4 NOT NULL,
    "max_duration" int4 NOT NULL,
    PRIMARY KEY ("member_type")
);