Question

I’m making a program and I need to make a query to the database asking for the string that appears most often in a given column. In this example, its “stringONE”.

----------------------------
|  ID  |  Column (string)  |
----------------------------
|  1   |     stringONE     |
----------------------------
|  2   |     stringTWO     |
----------------------------
|  3   |     stringONE     |
----------------------------
|  4   |     stringONE     |
----------------------------

Now I need to take the name of the string that appears the most and put it into a variable string, for example:

string most_appeared_string = sql.ExecuteScalar();

Also, what happens if there is no string that appears the most, rather 2 or more strings that appear the same amount of times, like this:

----------------------------
|  ID  |  Column (string)  |
----------------------------
|  1   |     stringONE     |
----------------------------
|  2   |     stringTWO     |
----------------------------
|  3   |     stringTWO     |
----------------------------
|  4   |     stringONE     |
----------------------------

Thanks ahead.

---

@KeithS

Do you have an sql-server version of the query because I’m getting some errors when trying it there. Here’s a table example of what I’d like to do precisely.

------------------------------------------------
|  ID  |  column1 (string) |  author (string)  |
------------------------------------------------
|  1   |     string-ONE    |       John        |
------------------------------------------------
|  2   |     string-TWO    |       John        |
------------------------------------------------
|  3   |     string-ONE    |      Martin       |
------------------------------------------------
|  4   |     string-ONE    |       John        |
------------------------------------------------

SELECT TOP (1) column1, COUNT(*) FROM table WHERE author='John' ORDER BY ID

It should return “string-ONE” since it appears the most (2) times for the author John. When trying the query in MS-SQL Management Studio though, this is the error I’m getting:

Column 'table.column1' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause.

---

Nevermind the edit. Thank you.

Answer 1

This is a pretty easy query (in T-SQL at least):

select top 1 Column, Count(*) from Table group by Column order by Count(*) desc

ExecuteScalar, by an implementation detail, will return the string value because it’s the first column of the only row in the result set, even though there are two columns. You could also use ExecuteReader to access the number of times that string occurs.