Question

我正在努力实现案例3 ：

案例1 ：客户已注册，但尚未下订单。该查询给出了案例1的结果。

    SELECT c.customers_id, 
       c.customers_firstname, 
       c.customers_lastname, 
       c.customers_email_address, 
       c.customers_telephone, 
       c.customers_fax, 
       ab.entry_street_address, 
       ab.entry_city, 
       ab.entry_state, 
       ab.entry_country_id, 
       ab.entry_postcode 
FROM   customers c 
       JOIN address_book ab 
         ON c.customers_id = ab.customers_id 
       JOIN customers_info ci 
         ON c.customers_id = ci.customers_info_id 
WHERE  ci.customers_info_date_account_created BETWEEN 
       '2014-10-25' AND '2015-10-10'

案例2：客户已注册并已下订单。此查询从订单表获取其他交付信息。以下查询适用于案例2。

SELECT c.customers_id, 
       c.customers_firstname, 
       c.customers_lastname, 
       c.customers_email_address, 
       c.customers_telephone, 
       c.customers_fax, 
       ab.entry_street_address, 
       ab.entry_city, 
       ab.entry_state, 
       ab.entry_country_id, 
       ab.entry_postcode, 
       o.delivery_street_address, 
       o.delivery_city, 
       o.delivery_state, 
       o.delivery_country, 
       o.delivery_postcode 
FROM   customers c 
       JOIN address_book ab 
         ON c.customers_id = ab.customers_id 
       JOIN orders o 
         ON c.customers_id = o.customers_id 
WHERE  o.date_purchased BETWEEN '2014-10-25' AND '2015-10-10'

案例3（我想要实现的目标）：我想让所有客户在特定时间段内注册使用

ci.customers_info_date_account_created BETWEEN＆＃39; 2014-10-25＆＃39;和＆＃39; 2015-10-10＆＃39;

另外，我想检查客户是否使用o.date_purchased BETWEEN＆＃39; 2014-10-25＆＃39;和＆＃39; 2015-10-10＆＃39;。如果下订单，则从订单表中获取所有交货信息。如果没有下订单，则将这些列留空。

o.delivery_street_address，o.delivery_city，o.delivery_state，o.delivery_country，o.delivery_postcode

Answer 1

将JOIN orders o更改为LEFT JOIN orders o（将填充NULL行），然后将您的条件更改为

WHERE (o.date_purchased BETWEEN '2014-10-25' AND '2015-10-10' OR o.customers_id IS NULL)

这会找到任何在该时间范围内有订单的人，或者尚未下订单的客户。

Answer 2

    SELECT c.customers_id, 
       c.customers_firstname, 
       c.customers_lastname, 
       c.customers_email_address, 
       c.customers_telephone, 
       c.customers_fax, 
       ab.entry_street_address, 
       ab.entry_city, 
       ab.entry_state, 
       ab.entry_country_id, 
       ab.entry_postcode,
       o.delivery_street_address, o.delivery_city, o.delivery_state, o.delivery_country, o.delivery_postcode  
FROM   customers c 
       INNER JOIN address_book ab 
         ON c.customers_id = ab.customers_id 
       INNER JOIN customers_info ci 
         ON c.customers_id = ci.customers_info_id
       LEFT JOIN (select * from orders where date_purchased BETWEEN '2014-10-25' AND '2015-10-10') o
         ON c.customers_id = o.customers_id 
WHERE  ci.customers_info_date_account_created BETWEEN 
       '2014-10-25' AND '2015-10-10'

您可以在子查询中列出字段名称而不是*。

Answer 3

使用LEFT JOIN。这将从第一个表中返回第二个表中没有任何匹配项的行。

SELECT c.customers_id, 
       c.customers_firstname, 
       c.customers_lastname, 
       c.customers_email_address, 
       c.customers_telephone, 
       c.customers_fax, 
       ab.entry_street_address, 
       ab.entry_city, 
       ab.entry_state, 
       ab.entry_country_id, 
       ab.entry_postcode, 
       o.delivery_street_address, 
       o.delivery_city, 
       o.delivery_state, 
       o.delivery_country, 
       o.delivery_postcode 
FROM   customers c 
JOIN address_book ab 
    ON c.customers_id = ab.customers_id 
JOIN customer_info ci
    ON c.customers_id = ci.customers_info_id
LEFT JOIN orders o 
    ON c.customers_id = o.customers_id AND o.date_purchased BETWEEN '2014-10-25' AND '2015-10-10' 
WHERE ci.customers_info_date_account_created BETWEEN '2014-10-25' AND '2015-10-10'

o.date_purchased上的配置被移入ON子句，因为从不匹配的行返回的NULL值与BETWEEN子句不匹配。

选择具有可选条件

3 个答案: