Changes between Version 1 and Version 2 of AdvancedReport20

Timestamp:

12/29/25 20:08:04 (4 days ago)

Author:

211101

Comment:

--

AdvancedReport20

@@ -1 @@
-===== Трансакции според тагови со највисоко трошење за цел систем
+==== Трансакции според тагови со највисоко трошење за цел систем
 {{{#!sql
-SELECT 
-    tg.tag_name, 
-    SUM(tb.spent_amount) AS total_spent
-FROM 
-    transaction_breakdown tb
-JOIN transaction t ON tb.transaction_id = t.transaction_id
-JOIN tag_assigned_to_transaction tat ON t.transaction_id = tat.transaction_id
-JOIN tag tg ON tat.tag_id = tg.tag_id
-GROUP BY 
-    tg.tag_name
-ORDER BY 
-    total_spent DESC;
+CREATE OR REPLACE FUNCTION get_total_spent_by_tag_system()
+RETURNS TABLE (
+    tag_name TEXT,
+    total_spent NUMERIC
+)
+LANGUAGE plpgsql
+AS $$
+BEGIN
+    RETURN QUERY
+    SELECT 
+        tg.tag_name, 
+        COALESCE(SUM(tb.spent_amount), 0) AS total_spent
+    FROM transaction_breakdown tb
+    JOIN transaction t 
+        ON tb.transaction_id = t.transaction_id
+    JOIN tag_assigned_to_transaction tat 
+        ON t.transaction_id = tat.transaction_id
+    JOIN tag tg 
+        ON tat.tag_id = tg.tag_id
+    GROUP BY tg.tag_name
+    ORDER BY total_spent DESC;
+END;
+$$;
 }}}
+
+==== Релациона алгебра
+- TB(transaction_id, spent_amount)
+- T(transaction_id, date)
+- TAT(tag_id, transaction_id)
+- TG(tag_id, tag_name)
+
+JOIN на сите табели:
+- J1 ← TB ⨝,,TB.transaction_id = T.transaction_id,, T
+- J2 ← J1 ⨝,,T.transaction_id = TAT.transaction_id,, TAT
+- J3 ← J2 ⨝,,TAT.tag_id = TG.tag_id,, TG
+
+Групирање и агрегација по таг:
+- G ← γ,,tag_name; SUM(spent_amount) → total_spent,,(J3)
+
+Подредување по вкупно потрошено:
+- R_final ← τ,,total_spent DESC,,(G)