<< SQL must know will be >> - Note 2

Accordance with the guidelines of the book, use MySQL as DBMS, you need to create before using sentence table
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following is uncommented SQL script
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Retrieving data

SELECT

Single row

   SELECT prod_name
   FROM Products;

Multi-row

   SELECT prod_id, prod_name, prod_price
   FROM Products;

All columns

Tsuhaifu *

   SELECT *
   FROM Products;

Different search values

If the result have the same value, only once

   SELECT DISTINCT vend_id
   FROM Products;

Limit your search results

Return result does not exceed X line

   SELECT prod_name 
   FROM Products 
   LIMIT 5 OFFSET 5;

5 shows a later date from the fifth row
described above can also be written

   SELECT prod_name 
   FROM Products 
   LIMIT 5,5;

Three kinds of comments

--，#，/**/

Sort Your Results

ORDER BY

Sequence

  SELECT prod_name
  FROM Products
  ORDER BY prod_name;

Sort by multiple columns

  SELECT prod_id, prod_price, prod_name 
  FROM Products 
  ORDER BY prod_price, prod_name;

Sort by Location column

  SELECT prod_id, prod_price, prod_name 
  FROM Products 
  ORDER BY 2,3;

Specify the sort direction

ASCOr DESC, by default ascending

  SELECT prod_id, prod_price, prod_name 
  FROM Products 
  ORDER BY prod_price DESC;

Filtering data

WHERE

A single value

  SELECT prod_name, prod_price
  FROM Products 
  WHERE prod_price = 3.49;

Mismatch

  SELECT prod_name, prod_price
  FROM Products 
  WHERE prod_price <> 'DLLO1';

The range of values

  SELECT prod_name, prod_price
  FROM Products 
  WHERE prod_price BETWEEN 5 AND 10;

Null

  SELECT cust_name
  FROM CuStomers
  WHERE cust_email IS NULL;

Advanced data filtering

Combining WHERE

AND

  SELECT prod_id, prod_price, prod_name
  FROM Products
  WHERE vend_id = 'DLL01' AND prod_price <= 4;

OR

  SELECT prod_name, prod_price 
  FROM Products 
  WHERE vend_id = 'DLL01' OR vend_id = 'BRS01';

AND higher priority than OR, if necessary, to determine the priority brackets

  SELECT prod_name, prod_price 
  FROM Products
  WHERE (vend_id = 'DLL01' OR vend_id = 'BRS01')
  AND prod_price >= 10;

IN

  SELECT prod_name, prod_price 
  FROM Products 
  WHERE vend_id IN ( 'DLL01', 'BRS01' )
  ORDER BY prod_name;

NOT

  SELECT prod_name 
  FROM Products 
  WHERE NOT vend_id = 'DLL01'
  ORDER BY prod_name DESC;

Tsuhaifu

LIKE

%Tsuhaifu

Appear to represent any character any number of times, including zero

  SELECT prod_id, prod_name 
  FROM Products 
  WHERE prod_name LIKE 'Fish%';

_Tsuhaifu

Matches any single character

  SELECT prod_id, prod_name 
  FROM Products 
  WHERE prod_name LIKE '__ inch teddy bear';

[]Tsuhaifu

Specify a character set
in MySQL 8 does not seem to be used with, and use RLIKE REGEXP and brackets with no
suggestion view the manuals section on regular expressions

  SELECT cust_contact
  FROM Customers 
  WHERE cust_contact regexp 'J%'
  ORDER BY cust_contact;
-- after test, the '[]' is useless