SQL · Case 03

360° View
Customer Success

LEFT JOIN combined with IS NULL to locate registered customers without orders, the gap between registration and usage driving early churn.

SQL
LEFT JOIN + IS NULL
Customer Success
Activation
LTV

−15 Days in activation time

LEFT JOIN Main technique

LTV Protected metric

Context

Customer Success strategy focused on activating new customers to reduce early churn through data cross-referencing.

About the case

It was suspected that many new customers were purchasing but showing high initial churn by not completing the first value action (activation) in the product. I used LEFT JOIN combined with IS NULL to identify gaps in the sales table, isolating registered customers without order records. Correctly identifying this base allowed proactive Customer Success interventions, reducing activation time by 15 days.

SQL

-- Identify customers without orders (activation gaps)

SELECT
    c.nome,
    c.email,
    c.data_cadastro
FROM
    clientes AS c
LEFT JOIN
    pedidos AS p ON c.id = p.cliente_id
WHERE
    p.id_pedido IS NULL;

Process visualization

Customers → orders → LEFT JOIN + IS NULL: the result isolates customers without orders

Business explanation

Customer success begins at onboarding. If a customer pays for a service and doesn't use it, cancellation is only a matter of time. SQL acts as a radar to identify the gap between registration and usage, allowing proactive intervention before the customer abandons the solution, protecting LTV.