Special usage of the SELECT command in MySQL

The SELECT command in MySQL is often used. The following describes some special usage of the SELECT command in MySQL for your reference.

The SELECT command in MySQL is similar to the print or write command in other programming languages. You can use it to display the results of a string, number, and mathematical expression. How to use the special features of the SELECT command in MySQL?

1. Display MYSQL version

 
 

  
  
mysql> select version();  
  
  
+-----------------------+  
  
  
| version()             |  
  
  
+-----------------------+  
  
  
| 6.0.4-alpha-community |  
  
  
+-----------------------+  
  
  
1 row in set (0.02 sec)  
  
  
 
 
 

2. display the current time

 
 

  
  
mysql> select now();  
  
  
+---------------------+  
  
  
| now()               |  
  
  
+---------------------+  
  
  
| 2009-09-15 22:35:32 |  
  
  
+---------------------+  
  
  
1 row in set (0.04 sec)  
  
  
 
 
 

3. Display year, month, and day

 
 

  
  
SELECT DAYOFMONTH(CURRENT_DATE);  
  
  
+--------------------------+  
  
  
| DAYOFMONTH(CURRENT_DATE) |  
  
  
+--------------------------+  
  
  
|                       15 |  
  
  
+--------------------------+  
  
  
1 row in set (0.01 sec)  
  
  
   
  
  
SELECT MONTH(CURRENT_DATE);  
  
  
+---------------------+  
  
  
| MONTH(CURRENT_DATE) |  
  
  
+---------------------+  
  
  
|                   9 |  
  
  
+---------------------+  
  
  
1 row in set (0.00 sec)  
  
  
   
  
  
SELECT YEAR(CURRENT_DATE);  
  
  
+--------------------+  
  
  
| YEAR(CURRENT_DATE) |  
  
  
+--------------------+  
  
  
|               2009 |  
  
  
+--------------------+  
  
  
1 row in set (0.00 sec)  
  
  
 
 
 

4. Display strings

 
 

  
  
mysql> SELECT "welecome to my blog!";  
  
  
+----------------------+  
  
  
| welecome to my blog! |  
  
  
+----------------------+  
  
  
| welecome to my blog! |  
  
  
+----------------------+  
  
  
1 row in set (0.00 sec)  
  
  
 
 
 

5. When using a calculator

 
 

  
  
select ((4 * 4) / 10 ) + 25;  
  
  
+----------------------+  
  
  
| ((4 * 4) / 10 ) + 25 |  
  
  
+----------------------+  
  
  
|                26.60 |  
  
  
+----------------------+  
  
  
1 row in set (0.00 sec)  
  
  
 
 
 

6. String concatenation

 
 

  
  
select CONCAT(f_name, " ", l_name)  
  
  
AS Name  
  
  
from employee_data  
  
  
where title = 'Marketing Executive';  
  
  
+---------------+  
  
  
| Name          |  
  
  
+---------------+  
  
  
| Monica Sehgal |  
  
  
| Hal Simlai    |  
  
  
| Joseph Irvine |  
  
  
+---------------+  
  
  
3 rows in set (0.00 sec)  
  
  
 
 
 

Note: The CONCAT () function is used to concatenate strings. In addition, we also use the previously learned AS to give the result column 'concat (f_name, "", l_name) 'A Kana.

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