Index: db.sql
===================================================================
--- db.sql	(revision 43)
+++ db.sql	(working copy)
@@ -102,21 +102,22 @@
 );
 
 CREATE TABLE ektith (
-    ekth_at_kwdikos integer         REFERENCES antik(at_kwdikos) ON DELETE CASCADE, --na allaxte se RESTRICT
-    ekth_ekth_kwdikos    integer    REFERENCES ekthesi(ekth_kwdikos) ON DELETE CASCADE,            
+    ekth_at_kwdikos   integer         REFERENCES antik(at_kwdikos) ON DELETE CASCADE, --na allaxte se RESTRICT
+    ekth_ekth_kwdikos integer    REFERENCES ekthesi(ekth_kwdikos) ON DELETE CASCADE,            
     PRIMARY KEY (ekth_at_kwdikos, ekth_ekth_kwdikos)
 );
 
 CREATE TABLE meso (
-    mes_kwdikos     serial          PRIMARY KEY,
-    mes_onoma       varchar(16)     UNIQUE,
-    mes_typos       varchar(16)
+    mes_kwdikos       serial          PRIMARY KEY,
+    mes_onoma         varchar(16)     UNIQUE,
+    mes_typos         varchar(16),
+    CHECK (mes_typos in ('tv', 'radio', 'efimerida', 'internet'))
 );
 
 CREATE TABLE diafimisi (
-    diaf_ekth_kwdik integer         REFERENCES ekthesi(ekth_kwdikos) ON DELETE RESTRICT,
-    diaf_mes_kwdik  integer         REFERENCES meso(mes_kwdikos) ON DELETE RESTRICT,
-    diaf_date       date,
-    diaf_kostos	    money,
+    diaf_ekth_kwdik   integer         REFERENCES ekthesi(ekth_kwdikos) ON DELETE RESTRICT,
+    diaf_mes_kwdik    integer         REFERENCES meso(mes_kwdikos) ON DELETE RESTRICT,
+    diaf_date         date,
+    diaf_kostos	      money,
     PRIMARY KEY (diaf_ekth_kwdik, diaf_mes_kwdik, diaf_date)
 );
Index: queries.sql
===================================================================
--- queries.sql	(revision 41)
+++ queries.sql	(working copy)
@@ -3,40 +3,48 @@
 
 -- emfanisi twn onomatwn olwn twn kallitexnon
 
-select distinct k.art_eponymo
-from artist k;
+--select distinct k.art_eponymo
+--from artist k;
 
+--select distinct art_eponymo from artist;
+--^^ den exei nohma to distinct
+
+
+
 --logw apografis ek8ematwn ola ta danismena prepei na epistrafoun stis 1/5/2008 (allagi1) OK
 
 update dan_se
 set dan_imer_ep =  '2008-05-01';
+--^^to field date tha to dinei o xrhsths
 
-SELECT * FROM dan_se;
+--to mouseio paei gia louketo opote meiwnei to kostos diafimisis se efimerides kata 50% (allagi2) OK
 
---to mouseio paei gia louketo opote meionei to kwstos diafimisis se efimerides  kata 50% (allagi2) OK
-
 update diafimisi
 set diaf_kostos = diaf_kostos*0.50
 from meso
 where mes_typos='efimerida';
+--^^ omoiws gia pososto kai meso
 
 --oi ek8eseis pou arxisan fetos  pairnoun paratasi mexri tis diakopes tou Pasxa  (allagi3) OK
-
 update ekthesi
 set ekth_im_liks = '2008-04-20'
 where  ekth_im_enarks>='2008-01-01';
 
+--^^ omoiws gia tis 2 imerominies
+
 --au3isiki tis timis tou eisitiriou kata 5% twn ek8esewn me pano apo 200 episkeptes (allagi4) OK
 
 update ekthesi
 set ekth_ticket=ekth_ticket*1.05
 where ekth_visitors>200;
 
+--....
+
 --afairesi olwn twn ergwn tou kallitexni Picasso mazi me ton idio ton kallitexni kai osous kallitexnes dn exoun erga (allagi5) OK
-
 delete from antik where at_kwdikos in (select fa_at_kwdikos from filot_apo, artist where fa_art_kwdik=art_kwdikos and art_eponymo='Picasso');
-delete from artist where art_kwdikos  not in ( select fa_art_kwdik from filot_apo);
+delete from artist where art_kwdikos not in (select fa_art_kwdik from filot_apo);
 
+--mipws na kratisoume mono to deytero ws "maintainance" vashs?
 
 --pe8ane o kalitexnis kakomoiris (allagi6) OK
 update artist
@@ -50,20 +58,32 @@
 select ekth_onoma, max(ekth_visitors)
 from ekthesi
 where ekth_im_enarks>='2008-01-01' and ekth_im_liks<='2008-12-31'
-group by ekth_onoma;
+group by ekth_onoma; --giati group by?
 
 --2 gia ka8e xwra emfanise ton giraiotero kallitexnh (aggr2) gia na exei pio poly noima 8a prepei kapws na to kanoume na emfanizetai kai o to onoma artist
+--select art_xwra, min(art_im_genn) from artist group by art_xwra;
+select art_xwra, art_onoma, art_eponymo, art_im_genn
+from artist 
+where (art_im_genn, art_xwra) in 
+    (select min(art_im_genn), art_xwra 
+    from artist 
+    group by art_xwra);
 
-select art_xwra, min(art_im_genn)  from artist group by art_xwra;
+--3 emfanise ka8e xwra pou ekproswpeitai apo toulaxiston 2 kallitexnes Renaissance  (having1) OK
+--select art_xwra
+--from artist
+--where art_epoxi='Renaissance'
+--group by art_xwra
+--having count(*)>=2;
 
-
---3 emfanise ka8e xwra pou ekproswpeitai apo toulaxiston 2 kallitexnes Renaissance  (having1) OK
-select art_xwra
+select art_xwra,art_epoxi
 from artist
-where art_epoxi='Renaissance'
-group by art_xwra
+where art_epoxi in (select distinct art_epoxi from artist)
+group by art_xwra,art_epoxi
 having count(*)>=2;
 
+--emfanizei olous tous syndiasmous xwrwn kai styl, mporoume na kanoume metavliti to >=$x
+
 --4 emfanise tous titlous ton antikeimenwn stul mparok pou einai stin monimi sullogh
 select at_titlos, at_perigrafh
 from antik 
@@ -71,29 +91,33 @@
 			(select at_kwd_syl 
 			from syllogh
 			where syl_onoma='Monimh syllogh');
+--metavliti to mparok?
 
 --5 emfanise ta erga pou filotexni8ikan stin xwra katagogis tou dimiourgou tous k tin xwra gennisis dimiourgou (join1) OK
+
 select at_titlos, art_eponymo, at_katagwgh
-from antik, artist
-where at_katagwgh=art_xwra
+from antik, artist, filot_apo
+where at_katagwgh=art_xwra and art_kwdikos=fa_art_kwdik and at_kwdikos=fa_at_kwdikos --kati den pigaine kala prin e?
 group by at_titlos, art_eponymo, at_katagwgh;
 
-
 --7 emfanise ola ta antikeimena pou einai daneismena k prepei na epistrafoun entos 15 imeron mazi me onoma upeu8unou (join3) OK
 select at_titlos, eks_ep_ypefth, eks_on_ypefth, til_ypefth
 from eks_syllogh, se_dan,  antik, til_ypefth
 where se_imer_ep-CURRENT_DATE<15 and eks_kwdikos=se_eks_kwdikos and se_imer_ep-CURRENT_DATE>=0  and se_at_kwdikos=at_kwdikos and eks_ep_ypefth=til_ep_ypefth;
 
+--?
 
 --6 na upen8umisoume ston upeu8uno oti prepei na mas epistrepsei antikeimmeno suntoma k pio antikeimeno OK
 select at_titlos, eks_ep_ypefth, til_til, dan_imer_ep
 from eks_syllogh, dan_se, til_ypefth, antik
 where dan_imer_ep-CURRENT_DATE<10  and dan_imer_ep-CURRENT_DATE>=0 and eks_kwdikos=dan_eks_kwdikos and eks_ep_ypefth=til_ep_ypefth and at_kwdikos=dan_at_kwdikos;
 
+--?
+
 --8 emfanisi olon ton trexouson ek8eseon me panw apo 2 ek8emata (having2) OK
 select ekth_onoma
 from ekthesi, ektith
-where ekth_im_enarks<CURRENT_DATE and ekth_im_liks>CURRENT_DATE and  ekth_ekth_kwdikos=ekth_kwdikos
+where ekth_im_enarks<CURRENT_DATE and ekth_im_liks>CURRENT_DATE and ekth_ekth_kwdikos=ekth_kwdikos
 group by ekth_onoma
 having count(*)>=2;
 
@@ -111,9 +135,10 @@
 		from meso, diafimisi
 		where mes_typos='internet' and mes_kwdikos=diaf_mes_kwdik) and ekth_im_enarks-CURRENT_DATE<30);
 
+--kourasmeno :(
 
 --11 parousiasi olwn twn antikeimenwn texnhs pou dn exoun perilif8ei se kapoia katigoria LOGIKA OK ALLA DN EXOUME DATA
-select *
+select * --mporei na mpei o titlos kai o kallitexnhs edw sto select
 from antik, allo
 where at_kwdikos=allo_at_kwdikos;
 
@@ -123,6 +148,36 @@
 where diaf_mes_kwdik=mes_kwdikos
 group by mes_typos;
 
+
+with diafimisi_meso (value,kwdikos) as
+    select max(diaf_kostos), diaf_mes_kwdik
+    from diafimisi
+    group by diaf_mes_kwdik
+
+
+select mes_typos, mes_onoma, diaf_kostos
+from diafimisi, meso
+where (diaf_mes_kwdik=mes_kwdikos) and (mes_typos, diaf_kostos) in
+    (select mes_typos, max(diaf_kostos)
+    from diafimisi, meso
+    group by mes_typos);
+
+--max diafimisi gia kathe meso
+select max(diaf_kostos), diaf_mes_kwdik
+from diafimisi
+group by diaf_mes_kwdik;
+
+
+select art_xwra, art_onoma, art_eponymo, art_im_genn
+from artist        
+where (art_im_genn, art_xwra) in
+    (select min(art_im_genn), art_xwra
+    from artist    
+    group by art_xwra);
+
+
+with max_diafimistiko_kostos (value) 
+
 --13 o ari8mos twn pinakwn modernas texnotropias pou uparxoun sto mouseio se monimh sullogh(join5) OK
 select count(*)
 from pinakas