Executing SQL query in Ruby

Question

I have this query in Ruby to fetch some data from the database:

@mastertest = connection.execute("select code_ver, date from mastertest")

So now I assume @mastertest is a 2-dimensional array containing all rows and columns

I try this to print everything out:

@mastertest.each do |row|
  puts row[0]
end

And it prints the first column of all rows.

Now I want to find out the unique values from the first column of all rows and count the number of it's occurrence too. I know it can be done through Hash or Array. Can someone help me with this?

megas · Accepted Answer · 2012-10-16 22:06:07Z

1

result = @mastertest.map{ |row| row[0] }.uniq
result.size #=> number of occurrences

edited Oct 16, 2012 at 22:06

answered Oct 16, 2012 at 21:45

megas

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4 Comments

Pi Horse Over a year ago

I want to assign the result to another 2d array to print the results....so should i do something like this: @temp = @mastertest.map{ |row| row[0] }.uniq.size ???

Pi Horse Over a year ago

Is result an array here? Because I am not getting the result I intend to get. To be more clear, the first row in my 2D-array will have data like this : 111,222,222,333,111 So my output should be a 2d array such that result=[ {111,2}, {222,2}, {333,1} ]

megas Over a year ago

Try to print to understand what kind of data you have "{ |row| puts row; row[0]}"

Pi Horse Over a year ago

I am quite new to ruby on rails...and when I make any changes in my controller, I cannot see the output being printed when i start my server.....I am testing my results by just making changes in my view....can you help me out here?

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