| 4 | | SELECT |
| 5 | | SUM(tb.spent_amount) AS credit_card_debt |
| 6 | | FROM |
| 7 | | transaction_breakdown tb |
| 8 | | JOIN transaction_account ta ON tb.transaction_account_id = ta.transaction_account_id |
| 9 | | JOIN transaction t ON tb.transaction_id = t.transaction_id |
| 10 | | WHERE |
| 11 | | ta.user_id = 101 -- ID на конкретниот корисник |
| 12 | | AND (ta.account_name ILIKE '%кредитна%' OR ta.account_name ILIKE '%credit%') |
| 13 | | AND EXTRACT(MONTH FROM t.date) = EXTRACT(MONTH FROM CURRENT_DATE - INTERVAL '1 MONTH') |
| 14 | | AND EXTRACT(YEAR FROM t.date) = EXTRACT(YEAR FROM CURRENT_DATE - INTERVAL '1 MONTH'); |
| | 4 | CREATE OR REPLACE FUNCTION get_credit_card_debt_last_month_user( |
| | 5 | p_user_id INT |
| | 6 | ) |
| | 7 | RETURNS TABLE ( |
| | 8 | credit_card_debt NUMERIC |
| | 9 | ) |
| | 10 | LANGUAGE plpgsql |
| | 11 | AS $$ |
| | 12 | BEGIN |
| | 13 | RETURN QUERY |
| | 14 | SELECT |
| | 15 | COALESCE(SUM(tb.spent_amount), 0) AS credit_card_debt |
| | 16 | FROM transaction_breakdown tb |
| | 17 | JOIN transaction_account ta |
| | 18 | ON tb.transaction_account_id = ta.transaction_account_id |
| | 19 | JOIN transaction t |
| | 20 | ON tb.transaction_id = t.transaction_id |
| | 21 | WHERE ta.user_id = p_user_id |
| | 22 | AND (ta.account_name ILIKE '%кредитна%' OR ta.account_name ILIKE '%credit%') |
| | 23 | AND EXTRACT(MONTH FROM t.date) = EXTRACT(MONTH FROM CURRENT_DATE - INTERVAL '1 MONTH') |
| | 24 | AND EXTRACT(YEAR FROM t.date) = EXTRACT(YEAR FROM CURRENT_DATE - INTERVAL '1 MONTH'); |
| | 25 | END; |
| | 26 | $$; |
| | 28 | |
| | 29 | ==== Релациона алгебра |
| | 30 | - TA(transaction_account_id, user_id, account_name) |
| | 31 | - TB(transaction_id, transaction_account_id, spent_amount) |
| | 32 | - T(transaction_id, date) |
| | 33 | |
| | 34 | JOIN на сите табели: |
| | 35 | - J1 ← TA ⨝,,TA.transaction_account_id = TB.transaction_account_id,, TB |
| | 36 | - J2 ← J1 ⨝,,TB.transaction_id = T.transaction_id,, T |
| | 37 | |
| | 38 | Филтрирање по корисник, кредитна картичка и минат месец: |
| | 39 | - F ← σ,,user_id = p_user_id ∧ (account_name ILIKE '%кредитна%' OR account_name ILIKE '%credit%') ∧ EXTRACT(MONTH FROM date) = EXTRACT(MONTH FROM CURRENT_DATE - INTERVAL '1 MONTH') ∧ EXTRACT(YEAR FROM date) = EXTRACT(YEAR FROM CURRENT_DATE - INTERVAL '1 MONTH'),,(J2) |
| | 40 | |
| | 41 | Агрегација на вкупен долг: |
| | 42 | - R_final ← γ,,; SUM(spent_amount) → credit_card_debt,,(F) |