Here is the schema for POP:

JOURNALS(j_num, j_name, j_subject_area, chief_editor_r_ssn[1])

chief_editor_rssn FK REF Researchers

 

ISSUES(j_num, i_num, i_date, i_num_pages)

j_num FK REF journals

 

RESEARCHERS(r_ssn, r_name, r_address, r_phone, r_institution)

 

ARTICLES(art_num, art_title, art_area_topic, art_abstract, j_num_submitted,date_submitted,

j_num_published, i_num_published)

j_num_submitted FK REF journals

(j_num_published,i_num) FK REF issues

 

AREA_EDITS(j_num, r_ssn)

j_num FK REF journals

r_ssn FK REF researchers

 

WRITES(r_ssn, art_num)

r_ssn FK REF researchers

art_num FK REF articles

 

REVIEWS(r_ssn, art_num)

r_ssn FK REF researchers

art_num FK REF articles

 

RESEARCH_SPECIALTIES(r_spec_name)

 

RRS(r_ssn, r_spec_name)

r_ssn FK REF researchers

spec_name FK REF research_specialties

 

 

Write SQL statements to answer the following queries.

a)    The name of the journal with the maximum number of area-editors.

b) The number of area editors for the journal in which article number 5471 appeared.

c)    The number of journals for which researcher ‘Albert Einstein’ is the chief editor.

d)   The average number of articles written by researchers at TU. 

e) The article area topic that has the maximum number of articles

[1] The chief_editor_r_ssn is the r_ssn of the researcher who is chief editor for the journal.