MYSQL在保留a.table id的同时左连接A.table和b.table

Question

MYSQL Left join A.table and b.table while retaining a.table id when there is no b.table match.

SELECT * FROM sales_customer a LEFT JOIN sales_contact b
ON a.customer_id = b.customer_id
ORDER BY CASE WHEN company_name = '' THEN lname ELSE company_name END ASC

Gets me this:

Array (
  [0] => 54
  [customer_id] => 
)

When there is no b.table match.

I need this:

Array (
  [0] => 54
  [customer_id] => 29 
)

Any suggestions?

The solution below worked. Thanks for your help.

SELECT *, COALESCE(a.customer_id, 0) AS customer_id FROM sales_customer a LEFT OUTER JOIN sales_contact b ON a.customer_id = b.customer_id ORDER BY CASE WHEN company_name = '' THEN lname ELSE company_name END ASC

Answer 1

Use it like this:

SELECT 
    *,
    COALESCE(b.customer_id, 0) AS customer_id
FROM sales_customer a 
LEFT JOIN sales_contact b ON a.customer_id = b.customer_id
ORDER BY 
    CASE WHEN company_name = '' THEN lname ELSE company_name END ASC