LEFT JOIN

sql

SELECT c.customer_id, c.name, o.order_id
FROM customers c
LEFT JOIN orders o ON o.customer_id = c.customer_id;

Explanation

Rows from `customers` without a matching order still appear, with right-side columns as `NULL`.

Learn the surrounding workflow

Compare similar commands or jump into common fixes when this command is part of a bigger troubleshooting path.

Same sheet · prioritizing Join types at a glance

Return only rows that match on both sides.

Open In sheetsqlsame section

Keep all rows from the right table and match rows from the left when available.

Open In sheetsqlsame section

Keep all rows from both tables and match where possible.

Open In sheetsqlsame section

Produce the Cartesian product of two tables.

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A `WHERE` clause can accidentally turn a left join into an inner join.

Open In sheetsql1 tag match

Prefer primary keys and foreign keys over names or free-form text.