Guruh talabasi Abdig’opporov javoxir Mysql 1-2-amaliy ishlar

SELECT with Subquery
In the previous many-to-many product sales example, how to find the suppliers that do not supply any product? You can query for the suppliers that supply at least one product in the products_suppliers table, and then query the suppliers table for those that are not in the previous result set.
mysql> SELECT suppliers.name from suppliers
WHERE suppliers.supplierID
NOT IN (SELECT DISTINCT supplierID from products_suppliers);
Can you do this without sub-query?
A subquery may return a scalar, a single column, a single row, or a table. You can use comparison operator (e.g., '=', '>') on scalar, IN or NOT IN for single row or column, EXISTS or NOT EXIST to test for empty set.
INSERT|UPDATE|DELETE with Subquery
You can also use a subquery with other SQL statements such as INSERT, DELETE, or UPDATE. For example,
-- Supplier 'QQ Corp' now supplies 'Pencil 6B'
-- You need to put the SELECT subqueies in parentheses
mysql> INSERT INTO products_suppliers VALUES (
(SELECT productID FROM products WHERE name = 'Pencil 6B'),
(SELECT supplierID FROM suppliers WHERE name = 'QQ Corp'));
-- Supplier 'QQ Copr' no longer supplies any item
mysql> DELETE FROM products_suppliers
WHERE supplierID = (SELECT supplierID FROM suppliers WHERE name = 'QQ Corp');
5.2 Working with Date and Time
Date and time are of particular interest for database applications. This is because business records often carry date/time information (e.g., orderDate, deliveryDate, paymentDate, dateOfBirth), as well as the need to time-stamp the creation and last-update of the records for auditing and security.
With date/time data types, you can sort the results by date, search for a particular date or a range of dates, calculate the difference between dates, compute a new date by adding/subtracting an interval from a given date.
Date By Example
Let's begin with Date (without Time) with the following example. Take note that date value must be written as a string in the format of 'yyyy-mm-dd', e.g., '2012-01-31'.
-- Create a table 'patients' of a clinic
mysql> CREATE TABLE patients (