Common query statements for the MySQL Getting Started tutorial

Sample database:

CREATE TABLE Shop (
Article INT (4) UNSIGNED zerofill DEFAULT ' 0000 ' not NULL,
Dealer CHAR DEFAULT ' not NULL,
Price DOUBLE (16,2) DEFAULT ' 0.00 ' is not NULL,
PRIMARY KEY (article, dealer));

INSERT into Shop VALUES
(1, ' a ', 3.45), (1, ' B ', 3.99), (2, ' a ', 10.99), (3, ' B ', 1.45),
(3, ' C ', 1.69), (3, ' d ', 1.25), (4, ' d ', 19.95);

Mysql> SELECT * from shop;
+---------+--------+-------+
| Article | dealer | Price |
+---------+--------+-------+
| 0001 |  A | 3.45 |
| 0001 |  B | 3.99 |
| 0002 | A | 10.99 |
| 0003 |  B | 1.45 |
| 0003 |  C | 1.69 |
| 0003 |  D | 1.25 |
| 0004 | D | 19.95 |
+---------+--------+-------+

1. Column Maximum value

What's the biggest item number?

SELECT MAX (article) from shop;

2. The row that owns the maximum value of a column

Find out the numbers, sellers and prices of the most expensive items?

Select article, Dealer price    from   shop    where  price= (select MAX (price) from the shop); Another solution is to sort all the rows in descending order and use the MySQL-specific limit clause to get to the first line:

SELECT article, dealer, price    from shop    order by Price desc    LIMIT 1;3. Column maximum: By group what is the maximum price for each item? SELECT article, MAX (price) as price
    from   Shop
    GROUP by article< br> +---------+-------+
| article | price |
+---------+-------+
|    0001 |  3.99 |
|& nbsp;   0002 | 10.99 |
|    0003 |  1.69 |
|    0004 | 19.95 |
+---------+-------+
4. Row with the maximum number of groups in a field for each item, find the most expensive items of the dealer? SELECT article, dealer, price
    from   shop S1
    where  price= ( SELECT MAX (s2.price)
              from shop S2
              WHERE s1.article = s2.article );
5. Use User variables to find the items with the highest or lowest price?

Mysql> SELECT @min_price: =min (Price), @max_price: =max (price) from shop;
Mysql> SELECT * from shop WHERE price= @min_price OR price= @max_price;
+---------+--------+-------+
| Article | dealer | Price |
+---------+--------+-------+
| 0003 |  D | 1.25 |
| 0004 | D | 19.95 |
+---------+--------+-------+
6. Search for two keywords that are grouped together by or by using two key searches:

SELECT Field1_index, field2_index from test_table WHERE field1_index = ' 1 ' OR field2_index = ' 1 '

You can also use union to synthesize the output of two separate SELECT statements together:

SELECT Field1_index, field2_index from test_table WHERE field1_index = ' 1 ' unionselect field1_index, Field2_index FRO M test_table WHERE field2_index = ' 1 ';