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SQL AVG Command |
AVG sql command is used to find out average value of a numeric field in a
table. Now let us apply this AVG command to this table and find out the
average mark
obtain by all the students. The AVG command will calculate the average
value of all the marks
| id |
name |
class |
mark |
| 1 |
John Deo |
Four |
75 |
| 2 |
Max Ruin |
Three |
85 |
| 3 |
Arnold |
Three |
55 |
| 4 |
Krish Star |
Four |
60 |
| 5 |
John Mike |
Four |
60 |
| 6 |
Alex John |
Four |
55 |
Same way we can get the minimum value of a range of records by using SQL MIN command. Also check up SQL MAX command to get highest value of data
We will apply the AVG command here like this to the field mark
SELECT avg( mark ) FROM `student`
The command will calculate average value of marks considering all the marks of
the table. We can define some header like this also.
SELECT AVG(mark) as avg_mark FROM `student`
Here we can use the Group
By command to find out the average mark obtained by each
classes.
SELECT class, avg( mark ) as avg_mark FROM
`student` GROUP BY class
| class |
avg_mark |
| Four |
62.5000 |
| Three |
70.0000 |
Please see the SQL SUM command to know the details
on uses of GROUP BY command and the
precautions.
We can add condition to the sql command to get our desired result. We can add
one Where clause to the query to consider records
for which mark is more than some value ( say 55 )
SELECT avg( mark ) as avg_mark, class FROM student where mark > 55 GROUP BY class
| avg_mark |
class |
| 65.0000 |
Four |
| 85.0000 |
Three |
Other sql commands like between can be used along with this
avg command to
find out required results.
| lotr | 04-04-2009 |
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| Note that on some mysql servers the autorounding is bad handled ... |
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