Complex SQL postgres query into ActiveRecord notation?
希望 ActiveRecord 向导可以帮助我确定这种查询是否可以使用 AR 语句完成，即无需执行原始 SQL 或深入 Arel？
我接近了，但似乎无法弄清楚如何添加子查询。我在 Rails 5.1.1 上。
1 2 3 4 5 6 | SELECT s.id AS stock_id, s.count, adjustments.count AS adjustment_count, adjustments.reason AS adjustment_reason FROM (SELECT * FROM stocks WHERE inventory_id = 6) AS s LEFT JOIN adjustments ON (s.id = adjustments.stock_id AND adjustments.reason='run_use') |
最终结果应该是所有库存 id 为 6 的库存，额外的列显示对它们进行的调整(如果存在)。
如果我在 Navicat 中运行 RAW SQL，我会得到这个结果，这就是我试图通过 ActiveRecord 得到的结果：
1 2 3 | Stock.where(inventory:6) .left_joins(:adjustments) .where("adjustments.reason = 'run_use'") |
其中一个应该适合你：
1 2 | Stock.eager_load(:adjustments) .where("adjustments.reason = ? OR stocks.inventory_id = ?","run_use", 6) |
或
1 2 | Stock.eager_load(:adjustments) .where(adjustments: { reason:"run_use" }, inventory_id = 6) |
嗯。看来您是想说：
Give me all Stock that belong to Inventory with id = 6 that also have Adjustments with a reason of 'run use'.
怎么样：
1 2 3 4 | Stock. WHERE(inventory_id: 6). joins(:adjustments). WHERE(adjustments: { reason: 'run_use' }) |
来自指南