MySQL查询WHERE关键字问题求助：含错误SQL语句需排查

嘿，我一眼就找到问题啦！你的SQL语句末尾误用了WHEN关键字，这里应该用WHERE来做全局行过滤，这就是phpMyAdmin报错的根源。

问题分析 #

在MySQL语法里：

• WHEN只能用在CASE表达式（比如你语句里判断客户状态的部分）或者JOIN ... ON的关联条件中；
• 如果要过滤整个查询结果里的行，必须使用WHERE子句。

你的语句最后想筛选出delete_status = 0的活跃客户，所以这里的WHEN完全不符合语法规范，换成WHERE就能解决问题。

修正后的完整查询语句 #

SELECT 
    c.name as "Client Name",
    c.email as "Email",
    c.phone as "Phone",
    cnt.name as "Country",
    c.street as "Street",
    c.city_id as "City/Suburb",
    st.name as "State",
    c.zip_code as "Postcode",
    "" as "Total Paid",
    "" as "Total Owed",
    CASE WHEN c.delete_status = 1 THEN "Not Active" ELSE "Active" END as "Status"
FROM customer c
LEFT JOIN shipping_address s ON c.id = s.customer_id
LEFT JOIN states st ON st.id = c.state_id
LEFT JOIN countries cnt ON cnt.id = c.country_id
WHERE c.delete_status = 0

内容的提问来源于stack exchange，提问作者DhavalThakor