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我想将在搜索字段中输入的日期（例如 04.07.2012）与我表中的日期（datetime名为 的列date）进行比较。但是，我似乎无法直接获得我的 SQL 查询。

我尝试了什么：

find(:all, :conditions => ['\'to_timestamp(date, \'DD Mon YYYY\')\' LIKE \'to_timestamp(?, \'DD Mon YYYY\')\'', '#{query}'])

但它失败了：

PG::Error: ERROR:  syntax error at or near "DD"
LINE 1: ...s".* FROM "projects"  WHERE ('to_timestamp(date, 'DD Mon YYY...
                                                             ^
: SELECT "pacients".* FROM "projects"  WHERE ('to_timestamp(date, 'DD Mon YYYY')' LIKE 'to_timestamp('#{query}', 'DD Mon YYYY')')

就（postgre）SQL 而言，我是一个真正的新手，我真的很感激在编写这个查询的正确方向上的一些提示。

太感谢了！

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1 回答 1

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As meager pointed out there are a couple of issues here:

  • incorrect string interpolation
  • making the database do more work than necessary and using LIKE when you can do date searching more directly:

Let ActiveRecord format the date inputs use straight SQL to compare the dates, something like:

start_date = Date.civil(2012, 7, 4)
end_date = Date.civil(2012, 7, 20)
User.where(["date BETWEEN ? AND ?", start_date, end_date])

Converting the source date and the dates in the database to a timestamp formatted like a string and then using LIKE is very round-about and poor performing as well.

于 2012-07-04T18:09:27.353 回答