我目前正在使用postgresql，并且有一个这样的表：有3列包含链接到位置表的位置id。在location表中有location\u id和location\u name。是否可以创建一个允许我显示位置名称而不是位置ID的查询？
wqlqzqxt1#
使用多个左连接：
select bt.transaction_id, bt.datetime, l1.location_name as location_1_name, l2.location_name as location_2_name, l3.location_name as location_3_namefrom base_table bt left join location l1 on l1.location_id = bt.location_1 left join location l2 on l1.location_id = bt.location_2 left join location l3 on l1.location_id = bt.location_3
select bt.transaction_id,
bt.datetime,
l1.location_name as location_1_name,
l2.location_name as location_2_name,
l3.location_name as location_3_name
from base_table bt
left join location l1 on l1.location_id = bt.location_1
left join location l2 on l1.location_id = bt.location_2
left join location l3 on l1.location_id = bt.location_3
1条答案
按热度按时间wqlqzqxt1#
使用多个左连接：