[英]Convert SQL Statement to Rails ActiveRecord
我想将以下代码转换为Rails Ruby代码:
SELECT * FROM ALBUMS
WHERE TITLE='Greatest Hits'
AND ARTIST='The Beatles';
SELECT COUNT(ID) FROM ALBUMS
WHERE TITLE='Greatest Hits'
AND ARTIST='The Beatles';
首先,我已经了解了Ruby中的pluck方法,但由于多种限制,在这种情况下,不仅标题,而且还有艺术家,我都不知道如何采摘。
第二,我只想计算标题和艺术家相同的出现次数。
请帮忙? 我最好的资料来源: http : //apidock.com/rails/ActiveRecord/Calculations/pluck
SELECT * FROM ALBUMS
WHERE TITLE='Greatest Hits'
AND ARTIST='The Beatles';
假设一个名为专辑的模型
Album.where(title: "Greatest Hits", artist: "The Beatles")
对于第二
SELECT COUNT(ID) FROM ALBUMS
WHERE TITLE='Greatest Hits'
AND ARTIST='The Beatles';
使用count
方法。
Album.where(title: "Greatest Hits", artist: "The Beatles").count(:id)
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