MYSQL左连接A.table和b.table，同时保留a.table id [英] MYSQL Left join A.table and b.table while retaining a.table id

问题描述

在没有b.table匹配项的情况下，MYSQL左连接A.table和b.table，同时保留a.table id.

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

给我这个:

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

没有b.table匹配项时.

When there is no b.table match.

我需要这个:

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

有什么建议吗?

以下解决方案有效.感谢您的帮助.

The solution below worked. Thanks for your help.

SELECT *，COALESCE(a.customer_id，0)AS customer_id FROM sales_customer a左外部联接sales_contact b ON a.customer_id = b.customer_id ORC BY FOR CASE WHEN company_name =``THEn lname ELSE company_name END ASC

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

推荐答案

像这样使用它:

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

这篇关于MYSQL左连接A.table和b.table，同时保留a.table id的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！