Rails：在数据库中搜索部分日期时间

Question

I have a problem. In my application I have a list with data. This data includes a datetime_utc column. There is also a searchbar which allows the user to search for datetime strings, but the searchbar is now requiring precise inputs, so for example these inputs return a result:

2023-01-01 02:00:00
2023-01-01 02:00
2023-01-01 02

As long as the input string starts with a valid datetime format. What I want is for example to look for only a given time like:

02:00

This should return all data with the time 02:00:00 as datetime_utc value. Right now this is my code:

data = data.where(datetime_utc: "#{params[:search]}") if params[:search] && params[:search] != ''

And I have tried things like this:

data = data.where("to_char(datetime_utc, 'YYYY-MM-DD HH24:MI:SS') LIKE ?": "%#{params[:search]}%") if params[:search] && params[:search] != ''

But this gives me the error:

PG::UndefinedColumn: ERROR:  column candlesticks.to_char(datetime_utc, 'YYYY-MM-DD HH24:MI:SS') LIKE ? does not exist

So I understand that Postgres formats the given input string to a datetime format first and I it can't do that, it crashes.

There must be a way to still get this to work right?

Answer 1

Rails is considering "to_char(datetime_utc, 'YYYY-MM-DD HH24:MI:SS') LIKE?" as column name because of the incorrect format used

You need to change your query to (Notice the : is replaced with , )

data = data.where("to_char(datetime_utc, 'YYYY-MM-DD HH24:MI:SS') LIKE ?", "%#{params[:search]}%") if params[:search] && params[:search] != ''