Marek Smorag recruitment task submission

calculate_largest_expensors.sql

@@ -0,0 +1,28 @@
+WITH expenses_calculated AS (
+    SELECT
+        employee_id,
+        -- Calculate total expense for each record
+        (unit_price * quantity) AS expense
+    FROM memory.default.expense
+),
+
+expenses_aggregated_filtered AS (
+    SELECT
+        employee_id,
+        -- Sum up the expenses for each employee
+        SUM(expense) AS total_expense
+    FROM expenses_calculated
+    GROUP BY employee_id
+)
+
+SELECT
+    ex.employee_id,
+    em.manager_id,
+    ex.total_expense AS total_expensed_amount,
+    CONCAT(em.first_name, ' ', em.last_name) AS employee_name,
+    CONCAT(ma.first_name, ' ', ma.last_name) AS manager_name
+FROM expenses_aggregated_filtered AS ex
+LEFT JOIN memory.default.employee AS em ON ex.employee_id = em.employee_id
+LEFT JOIN memory.default.employee AS ma ON em.manager_id = ma.employee_id
+WHERE ex.total_expense > 1000 -- Filter for employees with total expenses greater than 1000
+ORDER BY ex.total_expense DESC;

create_employees.sql

@@ -0,0 +1,21 @@
+-- Table creation
+CREATE TABLE memory.default.EMPLOYEE (
+    employee_id TINYINT,
+    first_name VARCHAR,
+    last_name VARCHAR,
+    job_title VARCHAR,
+    manager_id TINYINT
+);
+
+
+-- Data Insertion
+INSERT INTO memory.default.EMPLOYEE VALUES
+(1, 'Ian', 'James', 'CEO', 4),
+(2, 'Umberto', 'Torrielli', 'CSO', 1),
+(3, 'Alex', 'Jacobson', 'MD EMEA', 2),
+(4, 'Darren', 'Poynton', 'CFO', 2),
+(5, 'Tim', 'Beard', 'MD APAC', 2),
+(6, 'Gemma', 'Dodd', 'COS', 1),
+(7, 'Lisa', 'Platten', 'CHR', 6),
+(8, 'Stefano', 'Camisaca', 'GM Activation', 2),
+(9, 'Andrea', 'Ghibaudi', 'MD NAM', 2);

create_expenses.sql

@@ -0,0 +1,17 @@
+-- Table creation
+CREATE TABLE memory.default.EXPENSE (
+    employee_id TINYINT,
+    unit_price DECIMAL(8, 2),
+    quantity TINYINT
+);
+
+
+-- Data Insertion
+INSERT INTO memory.default.EXPENSE VALUES
+(3, 6.50, 14),
+(3, 11, 20),
+(3, 22, 18),
+(3, 13, 75),
+(9, 300, 1),
+(4, 40, 9),
+(2, 17.50, 4);

create_invoices.sql

@@ -0,0 +1,52 @@
+CREATE TABLE memory.default.supplier AS
+WITH sorted_suppliers AS (
+    SELECT
+        name,
+        -- Assigning a unique ID based on alphabetical order
+        ROW_NUMBER() OVER (ORDER BY name) AS supplier_id
+    FROM (
+        VALUES -- List of suppliers from finance/invoices_due invoices
+        ('Party Animals'),
+        ('Catering Plus'),
+        ('Dave''s Discos'),
+        ('Entertainment tonight'),
+        ('Ice Ice Baby')
+    )
+)
+
+SELECT
+    CAST(supplier_id AS TINYINT) AS supplier_id,
+    name
+FROM sorted_suppliers;
+
+
+CREATE TABLE memory.default.invoice AS
+WITH transformed_invoices AS (
+    SELECT
+        supplier.supplier_id,
+        t.invoice_amount,
+        /* Calculating due date based on the number of months from the current date
+         The due date is the last day of the month that is 'due months' from now */
+        LAST_DAY_OF_MONTH(
+            DATE_ADD(
+                'MONTH', t.due_months, DATE_TRUNC('MONTH', CURRENT_DATE)
+            )
+
+        ) AS due_date
+    FROM
+        (
+            VALUES ('Party Animals', 6000, 3),
+            ('Catering Plus', 2000, 2),
+            ('Catering Plus', 1500, 3),
+            ('Dave''s Discos', 500, 1),
+            ('Entertainment tonight', 6000, 3),
+            ('Ice Ice Baby', 4000, 6)
+        ) AS t (supplier_name, invoice_amount, due_months)
+    LEFT JOIN memory.default.supplier ON t.supplier_name = supplier.name
+)
+
+SELECT
+    supplier_id,
+    CAST(invoice_amount AS DECIMAL(8, 2)) AS invoice_amount,
+    due_date
+FROM transformed_invoices;

find_manager_cycles.sql

@@ -0,0 +1,36 @@
+-- Find management cycles using recursive CTE
+WITH RECURSIVE managament_chain (employee_id, manager_id, chain) AS (
+    -- Entry point: select all employees with their direct managers
+    SELECT
+        employee_id,
+        manager_id,
+        ARRAY[employee_id, manager_id] AS chain
+    FROM memory.default.employee
+
+    UNION ALL
+    -- Recursive point: follow the chain of managers
+    SELECT
+        mc.employee_id, -- Root employee_id
+        e.manager_id, -- Get next manager in chain
+        array_union(mc.chain, ARRAY[e.manager_id]) AS chain -- Build chain array
+    FROM managament_chain AS mc
+    INNER JOIN memory.default.employee AS e
+        ON mc.manager_id = e.employee_id
+    WHERE NOT contains(mc.chain, e.manager_id) -- Prevent overlapping cycles
+),
+
+max_chain (employee_id, chain, max_size_chain) AS (
+    SELECT
+        employee_id,
+        chain,
+        max(cardinality(chain)) -- Get max size of the chain
+            OVER (PARTITION BY employee_id)
+            AS max_size_chain
+    FROM managament_chain
+)
+
+SELECT
+    employee_id,
+    chain
+FROM max_chain
+WHERE cardinality(chain) = max_size_chain; -- Select only records with full chain

generate_supplier_payment_plans.sql

@@ -0,0 +1,90 @@
+WITH invoice_aggregated AS ( -- Agggregate payments per supplier and due date
+    SELECT
+        supplier_id,
+        due_date,
+        -- Calculate total invoice amount per supplier and due date
+        sum(invoice_amount)
+            OVER (PARTITION BY supplier_id, due_date)
+            AS invoices_total_due_date,
+        sum(invoice_amount)
+            OVER (PARTITION BY supplier_id)
+            AS invoices_total_per_supplier
+    FROM memory.default.invoice
+),
+
+installment_per_invoice AS ( -- Calculate installment for 1 month
+    SELECT
+        supplier_id,
+        due_date,
+        -- Calculate installment per each invoice by
+        -- dividing total invoice amount by the number of month until due date
+        invoices_total_due_date
+        / (
+            (
+                date_diff(
+                    'MONTH',
+                    date_add('MONTH', 1, date_trunc('month', current_date)), -- Start from next month not current to match results with example
+                    date_trunc('month', due_date)
+                )
+            )
+            + 1
+        ) AS installment_per_due_date
+    FROM invoice_aggregated
+),
+
+-- Generate months in which installment is paid
+installment_per_invoice_per_month AS (
+    SELECT
+        i.supplier_id,
+        i.due_date,
+        i.installment_per_due_date,
+        payment_month
+    FROM installment_per_invoice AS i
+    CROSS JOIN
+    -- Explode due date into months between next month and due date
+        unnest(
+            sequence(
+                date_add('MONTH', 1, date_trunc('month', current_date)),
+                date_trunc('month', due_date),
+                INTERVAL '1' MONTH
+            )
+        )
+),
+
+total_installment_per_month AS ( -- Aggregate installments
+    SELECT
+        supplier_id,
+        payment_month,
+        sum(installment_per_due_date) AS payment_amount
+    FROM installment_per_invoice_per_month
+    GROUP BY supplier_id, payment_month
+),
+
+balance_outstanding_calculated AS ( -- Calculate balance outstanding per month
+    SELECT DISTINCT
+        t1.supplier_id,
+        s.name AS supplier_name,
+        t1.payment_amount,
+        t1.payment_month AS payment_date,
+        -- Sum of all payments that will be paid in the future
+        coalesce(
+            sum(t2.payment_amount)
+                OVER (PARTITION BY t1.supplier_id, t1.payment_month),
+            0
+        ) AS balance_outstanding
+    FROM total_installment_per_month AS t1
+    LEFT JOIN
+        total_installment_per_month AS t2
+        ON
+            t1.supplier_id = t2.supplier_id
+            AND t1.payment_month < t2.payment_month -- Future payments
+    LEFT JOIN memory.default.supplier AS s ON t1.supplier_id = s.supplier_id
+)
+
+SELECT
+    supplier_id,
+    supplier_name,
+    payment_amount,
+    balance_outstanding,
+    payment_date
+FROM balance_outstanding_calculated;