MySQL: Getting data for histogram plot? Source: http://stackoverflow.com/questions/1764881/mysql-getting-data-for-histogram-plot

hist.sql

SELECT ROUND(numeric_value, -2)    AS bucket,
       COUNT(*)                    AS COUNT,
       RPAD('', LOG(COUNT(*)), '*') AS bar
FROM   my_table
GROUP  BY bucket;
 
/*
numeric_value = column name
-2 to round in steps of 100. Use -1 for steps of 10 and any positive vale for rounding to nearest decimal
LOG(COUNT(*)) is to make the count on log scale
Output:
+--------+----------+-----------------+
| bucket | count    | bar             |
+--------+----------+-----------------+
|   -500 |        1 |                 |
|   -400 |        2 | *               |
|   -300 |        2 | *               |
|   -200 |        9 | **              |
|   -100 |       52 | ****            |
|      0 |  5310766 | *************** |
|    100 |    20779 | **********      |
|    200 |     1865 | ********        |
|    300 |      527 | ******          |
|    400 |      170 | *****           |
|    500 |       79 | ****            |
|    600 |       63 | ****            |
|    700 |       35 | ****            |
|    800 |       14 | ***             |
|    900 |       15 | ***             |
|   1000 |        6 | **              |
|   1100 |        7 | **              |
|   1200 |        8 | **              |
|   1300 |        5 | **              |
|   1400 |        2 | *               |
|   1500 |        4 | *               |
+--------+----------+-----------------+
*/