The MySQL SELECT command is something like a print or write command of other languages. You can ask it to display text strings, numeric data, the results of mathematical expressions etc.
Displaying the MySQL version number
select version();
+———–+
| version() |
+———–+
| 3.22.32 |
+———–+
1 row in set (0.00 sec)
Displaying the current date and time
select now();
+———————+
| now() |
+———————+
| 2001-05-31 00:36:24 |
+———————+
1 row in set (0.00 sec)
Displaying the current Day, Month and Year
SELECT DAYOFMONTH(CURRENT_DATE);
+————————–+
| DAYOFMONTH(CURRENT_DATE) |
+————————–+
| 28 |
+————————–+
1 row in set (0.01 sec)
SELECT MONTH(CURRENT_DATE);
+———————+
| MONTH(CURRENT_DATE) |
+———————+
| 1 |
+———————+
1 row in set (0.00 sec)
SELECT YEAR(CURRENT_DATE);
+——————–+
| YEAR(CURRENT_DATE) |
+——————–+
| 2001 |
+——————–+
1 row in set (0.00 sec)
Displaying text strings
select 'I Love MySQL';
+————–+
| I Love MySQL |
+————–+
| I Love MySQL |
+————–+
1 row in set (0.00 sec)
Obviously you can provide pseudo names for these columns using AS.
select 'Manish Sharma' as Name;
+—————+
| Name |
+—————+
| Manish Sharma |
+—————+
1 row in set (0.00 sec)
Evaluating expressions in MySQL
select ((4 * 4) / 10 ) + 25;
+———————-+
| ((4 * 4) / 10 ) + 25 |
+———————-+
| 26.60 |
+———————-+
1 row in set (0.00 sec)
Concatenating in MySQL
With SELECT you can concatenate values for display. CONCAT accepts arguments between parenthesis. These can be column names or plain text strings. Text strings have to be surrounded with quotes (single or double).
SELECT CONCAT(f_name, " ", l_name)
from employee_data
where title = 'Programmer';
+—————————–+
| CONCAT(f_name, " ", l_name) |
+—————————–+
| Fred Kruger |
| John MacFarland |
| Edward Sakamuro |
| Alok Nanda |
+—————————–+
4 rows in set (0.00 sec)
You can also give descriptive names to these columns using AS.
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)
Assignments:
1.Which command displays the MySQL version?
2.Use the SELECT command to evaluate 4 X 4 X 4 and name the column Cube of 4.
3.Display your name with SELECT.
Possible Answers:
1.mysql> select version();
+———–+
| version() |
+———–+
| 3.22.32 |
+———–+
1 row in set (0.00 sec)
2.mysql> select 4*4*4 as 'Cube of 4';
+———–+
| Cube of 4 |
+———–+
| 64 |
+———–+
1 row in set (0.00 sec)
Note: Any pseudo name that has spaces should be enclosed in quotes.
3.mysql> SELECT 'your_name';
+———–+
| your_name |
+———–+
| your_name |
+———–+
1 row in set (0.00 sec)
Note: Your name is a text string and has to be surrounded by quotes (single or double).