how to count rows by first letter?

Question

a noob question here!

I wrote this query, but the \"group by\" is very stupid... so, how can I correct this?

SELECT
    COUNT(*) AS total,
    \'x\'         


        

Answer 1

This should perform as well as any other option -

SELECT
    LEFT(name, 1) AS first_letter,
    COUNT(*) AS total
FROM contents
GROUP BY first_letter

If you want to run this query for a single letter at a time you can add the WHERE clause and drop the GROUP BY -

SELECT COUNT(*) AS total
FROM contents
WHERE name LIKE 'a%'

Answer 2

Let's dissect your query:

SELECT
    COUNT(*) AS total,
    'x' as test     <-- Why?
    FROM            <-- Bad formatting.
contents
    WHERE name LIKE 'C%'
GROUP BY
    test            <-- Removing 'x' and the whole GROUP BY has the same effect.
ORDER BY id ASC     <-- The result only contains one row - nothing to sort.

So the query that returns one row with one field, containing the number of rows whose name begins with 'C' would look like this:

SELECT COUNT(*)
FROM contents
WHERE name LIKE 'C%'

Having an index whose leading edge is name would ensure good performance. To understand why, take a look at the Anatomy of an SQL Index.

Answer 3

should give you everything in case you want it

SELECT
  COUNT(*) AS total,
  test
FROM
 (SELECT substring(name,1,1) as test
 from contents) t
GROUP BY test