MySQL - COUNT Function


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MySQL COUNT function is the simplest function and very useful in counting the number of records, which are expected to be returned by a SELECT statement.

To understand COUNT function, consider an employee_tbl table, which is having the following records −

mysql> SELECT * FROM employee_tbl;
+------+------+------------+--------------------+
|  id  | name | work_date  | daily_typing_pages |
+------+------+------------+--------------------+
|   1  | John | 2007-01-24 |        250         |
|   2  | Ram  | 2007-05-27 |        220         |
|   3  | Jack | 2007-05-06 |        170         |
|   3  | Jack | 2007-04-06 |        100         |
|   4  | Jill | 2007-04-06 |        220         |
|   5  | Zara | 2007-06-06 |        300         |
|   5  | Zara | 2007-02-06 |        350         |
+------+------+------------+--------------------+
7 rows in set (0.00 sec)

Now, suppose based on the above table you want to count total number of rows in this table, then you can do it as follows −

mysql>SELECT COUNT(*) FROM employee_tbl ;
+----------+
| COUNT(*) |
+----------+
|    7     |
+----------+
1 row in set (0.01 sec)

Similarly, if you want to count the number of records for Zara, then it can be done as follows −

mysql>SELECT COUNT(*) FROM employee_tbl
   -> WHERE name = "Zara";
+----------+
| COUNT(*) |
+----------+
|    2     |
+----------+
1 row in set (0.04 sec)

NOTE − All the SQL queries are case insensitive so it does not make any difference if you give ZARA or Zara in WHERE condition.


mysql-useful-functions.htm

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