activerecord - Check if Rails Database Query Returns Nothing -

I want to know if a railway database query returns a row or not (I do not need to know that the row , If just one row comes back).

I can do this:

  academic_yire = academic yair.find_b ____ input (year) if academic_array ... end   
 but If I type incorrectly and a  find_all_by :  
  academic_all = academic yair.find_all_b ____ input (year)   
 then a blank The array has been returned, due to which the  if  statement is correct.  
 I know, I need to be careful and just call  all , but there is a Rail-Asc call to see if any questions ( all < / Code> or not) returns result from  zero ?   
 
 
 As you said,  find_by _...  back  zero  []  will return  and  search_full____. . I think that what you see is that.  
  if! Academic_thank.bank? # ... end   
 in console  
  & gt; AcademicYear.find_by_raw_input (some_non_existent_year) .blank? = & Gt; True & gt; AcademicYear.find_all_by_raw_input (some_non_existent_year) .blank? = & Gt; True