Count particular substring text within column - sql

Question

I have a Hive table, titled 'UK.Choices' with a column, titled 'Fruit', with each row as follows:
AppleBananaAppleOrangeOrangePears
BananaKiwiPlumAppleAppleOrange
KiwiKiwiOrangeGrapesAppleKiwi
etc.
etc.
There are 2.5M rows and the rows are much longer than the above.
I want to count the number of instances that the word 'Apple' appears.
For example above, it is:
Number of 'Apple'= 5
My sql so far is:
select 'Fruit' from UK.Choices
Then in chunks of 300,000 I copy and paste into Excel, where I'm more proficient and able to do this using formulas. Problem is, it takes upto an hour and a half to generate each chunk of 300,000 rows.
Anyone know a quicker way to do this bypassing Excel? I can do simple things like counts using where clauses, but something like the above is a little beyond me right now. Please help.
Thank you.

Answer 1

I think I am 2 years too late. But since I was looking for the same answer and I finally managed to solve it, I thought it was a good idea to post it here.
Here is how I do it.
Solution 1:
+-----------------------------------+---------------------------+-------------+-------------+
| Fruits | Transform 1 | Transform 2 | Final Count |
+-----------------------------------+---------------------------+-------------+-------------+
| AppleBananaAppleOrangeOrangePears | #Banana#OrangeOrangePears | ## | 2 |
| BananaKiwiPlumAppleAppleOrange | BananaKiwiPlum##Orange | ## | 2 |
| KiwiKiwiOrangeGrapesAppleKiwi | KiwiKiwiOrangeGrapes#Kiwi | # | 1 |
+-----------------------------------+---------------------------+-------------+-------------+
Here is the code for it:
SELECT length(regexp_replace(regexp_replace(fruits, "Apple", "#"), "[A-Za-z]", "")) as number_of_apples
FROM fruits;
You may have numbers or other special characters in your fruits column and you can just modify the second regexp to incorporate that. Just remember that in hive to escape a character you may need to use \\ instead of just one \.
Solution 2:
SELECT size(split(fruits,"Apple"))-1 as number_of_apples
FROM fruits;
This just first split the string using "Apple" as a separator and makes an array. The size function just tells the size of that array. Note that the size of the array is one more than the number of separators.

Answer 2

This is straight-forward if you have any delimiter ( eg: comma ) between the fruit names. The idea is to split the column into an array, and explode the array into multiple rows using the 'explode' function.
SELECT fruit, count(1) as count FROM
( SELECT
explode(split(Fruit, ',')) as fruit
FROM UK.Choices ) X
GROUP BY fruit
From your example, it looks like fruits are delimited by Capital letters. One idea is to split the column based on capital letters, assuming there are no fruits with same suffix.
SELECT fruit_suffix, count(1) as count FROM
( SELECT
explode(split(Fruit, '[A-Z]')) as fruit_suffix
FROM UK.Choices ) X
WHERE fruit_suffix <> ''
GROUP BY fruit_suffix
The downside is that, the output will not have first letter of the fruit,
pple - 5
range - 4

Answer 3

I think you want to run in one select, and use the Hive if UDF to sum for the different cases. Something like the following...
select sum( if( fruit like '%Apple%' , 1, 0 ) ) as apple_count,
sum( if( fruit like '%Orange%', 1, 0 ) ) as orange_count
from UK.Choices
where ID > start and ID < end;
instead of a join in the above query.

Answer 4

No experience of Hive, I'm afraid, so this may or may not work. But on SQLServer, Oracle etc I'd do something like this:
Assuming that you have an int PK called ID on the row, something along the lines of:
select AppleCount, OrangeCount, AppleCount - OrangeCount score
from
(
select count(*) as AppleCount
from UK.Choices
where ID > start and ID < end
and Fruit like '%Apple%'
) a,
(
select count(*) as OrangeCount
from UK.Choices
where ID > start and ID < end
and Fruit like '%Orange%'
) o
I'd leave the division by the total count to the end, when you have all the rows in the spreadsheet and can count them there.
However, I'd urgently ask my boss to let me change the Fruit field to be a table with an FK to Choices and one fruit name per row. Unless this is something you can't do in Hive, this design is something that makes kittens cry.
PS I'd missed that you wanted the count of occurances of Apple which this won't do. I'm leaving my answer up, because I reckon that my However... para is actually a good answer. :(