# Can not convert array to string: problem of a newbie

**URL:** <https://www.ruby-forum.com/t/can-not-convert-array-to-string-problem-of-a-newbie/92417>\
**Category:** Development\
**Created:** [April 19, 2007, 11:37am UTC](https://www.ruby-forum.com/t/can-not-convert-array-to-string-problem-of-a-newbie/92417 "2007-04-19T11:37:46Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![snowbird122](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/c68b51/32.png) [@snowbird122](https://www.ruby-forum.com/u/snowbird122)\
**Post date:** [April 19, 2007, 11:37am UTC](https://www.ruby-forum.com/t/can-not-convert-array-to-string-problem-of-a-newbie/92417/1 "2007-04-19T11:37:46Z")

</div>

hi guys,

def fil\_string  
sql = ActiveRecord::Base.connection()  
filter\_string=’ ’  
sql.begin\_db\_transaction  
column\_ids = sql.execute(“SELECT columnid FROM output\_columns”)  
column\_ids.each do |column\_id|  
filter\_string=filter\_string +" columnid=’"+column\_id+"’"  
end  
sql.commit\_db\_transaction  
end

## but in the solution Error: can not convert array to string at line – filter\_string=filter\_string +" columnid=’"+column\_id+"’" "

Please take a hand in my code.