Changes between Version 1 and Version 2 of AdvancedReport15

Timestamp:

12/29/25 19:54:35 (4 days ago)

Author:

211101

Comment:

--

AdvancedReport15

@@ -1 @@
-===== Трендови на трошење според тагови за цел систем
+==== Трендови на трошење според тагови за цел систем
 Трендови на трошење за секој таг во последните шест месеци
 {{{#!sql
-SELECT 
-    tg.tag_name, 
-    DATE_TRUNC('month', t.date) AS month,
-    SUM(tb.spent_amount) AS total_spent
-FROM 
-    tag tg
-JOIN tag_assigned_to_transaction tat ON tg.tag_id = tat.tag_id
-JOIN transaction t ON tat.transaction_id = t.transaction_id
-JOIN transaction_breakdown tb ON t.transaction_id = tb.transaction_id
-WHERE 
-    t.date >= DATE_TRUNC('month', CURRENT_DATE - INTERVAL '6 MONTHS')
-GROUP BY 
-    tg.tag_name, month
-ORDER BY 
-    tg.tag_name, month;
+CREATE OR REPLACE FUNCTION get_spending_trends_last_6_months()
+RETURNS TABLE (
+    tag_name TEXT,
+    month DATE,
+    total_spent NUMERIC
+)
+LANGUAGE plpgsql
+AS $$
+BEGIN
+    RETURN QUERY
+    SELECT 
+        tg.tag_name, 
+        DATE_TRUNC('month', t.date) AS month,
+        COALESCE(SUM(tb.spent_amount), 0) AS total_spent
+    FROM tag tg
+    JOIN tag_assigned_to_transaction tat 
+        ON tg.tag_id = tat.tag_id
+    JOIN transaction t 
+        ON tat.transaction_id = t.transaction_id
+    JOIN transaction_breakdown tb 
+        ON t.transaction_id = tb.transaction_id
+    WHERE t.date >= DATE_TRUNC('month', CURRENT_DATE - INTERVAL '6 MONTHS')
+    GROUP BY tg.tag_name, month
+    ORDER BY tg.tag_name, month;
+END;
+$$;
 }}}
+
+==== Релациона алгебра
+- TG(tag_id, tag_name)
+- TAT(tag_id, transaction_id)
+- T(transaction_id, date)
+- TB(transaction_id, spent_amount)
+
+JOIN на сите табели:
+- J1 ← TG ⨝,,TG.tag_id = TAT.tag_id,, TAT
+- J2 ← J1 ⨝,,TAT.transaction_id = T.transaction_id,, T
+- J3 ← J2 ⨝,,T.transaction_id = TB.transaction_id,, TB
+
+Филтрирање на трансакции од последните 6 месеци:
+- F ← σ,,date >= DATE_TRUNC('month', CURRENT_DATE - INTERVAL '6 MONTHS'),,(J3)
+
+Групирање по таг и месец:
+- G ← γ,,tag_name, month = DATE_TRUNC('month', date); Σ(spent_amount) → total_spent,,(F)
+
+Подредување по таг и месец:
+- R_final ← τ,,tag_name, month,,(G)