basic sql tutorial
DESCRIPTION
Basic SQL TutorialTRANSCRIPT
Today’s Agenda
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Querying data from MySQL database1
Modifying data in MySQL2
Working with MySQL databases3
MySQL Globalization4
Download MySQL Sample Database
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Create new account
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SQL statement
CREATE USER 'user1'@'%' IDENTIFIED WITH mysql_native_password AS '***';
GRANT ALL PRIVILEGES ON *.* TO 'user1'@'%' REQUIRE NONE WITH GRANT OPTION;
CREATE DATABASE IF NOT EXISTS `user1`; GRANT ALL PRIVILEGES ON `user1`.* TO 'user1'@'%'; GRANT ALL PRIVILEGES ON `user1\_%`.* TO 'user1'@'%';
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SQL statement (REVOKE)
REVOKE ALL PRIVILEGES ON *.* FROM'user1'@'%'; GRANT SELECT ON *.* TO'user1'@'%' ;
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REVOKE ALL PRIVILEGES ON `user1`.* FROM 'user1'@'%'; GRANT ALL PRIVILEGESON `user1`.* TO 'user1'@'%' WITH GRANT OPTION;
SELECT Statement
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the syntax of the SELECT statement
SELECT
column_1, column_2, ...
FROM
table_1
WHERE
conditions
ORDER BY column_1 ;
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ตอ้งการขอ้มูลจาก 3 fields คือ lastName, firstName และ jobTitle
SELECT Statement
SELECT
lastname, firstname, jobtitle
FROM
employees;
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SELECT Statement
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Introduction to ORDER BY clause
SELECT column1, column2,...
FROM tbl
ORDER BY column1 [ASC|DESC], column2 [ASC|DESC],...
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Example of ORDER BY clause
SELECT
contactLastname, contactFirstname
FROM
customers
ORDER BY contactLastname;
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Example of ORDER BY clause
SELECT
contactLastname, contactFirstname
FROM
customers
ORDER BY contactLastname DESC;
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Example of ORDER BY clause
SELECT
ordernumber, orderlinenumber, FORMAT(quantityOrdered * priceEach, 2)
FROM
orderdetails
ORDER BY ordernumber , orderLineNumber, quantityOrdered * priceEach;
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Example of ORDER BY clause
SELECT
orderNumber, status
FROM
orders
ORDER BY FIELD (status, 'In Process', 'On Hold', 'Cancelled', 'Resolved', 'Disputed', 'Shipped');
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Using DISTINCT to Eliminate Duplicates
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syntax of using the DISTINCT clause
SELECT DISTINCT
columns
FROM
table_name
WHERE
where_conditions;
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DISTINCT example 1
SELECT
lastname
FROM
employees
ORDER BY lastname;
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DISTINCT example 2
SELECT DISTINCT
lastname
FROM
employees
ORDER BY lastname;
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DISTINCT with multiple columns
SELECT DISTINCT
state, city
FROM
customers
WHERE
state IS NOT NULL
ORDER BY state , city;
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DISTINCT with multiple columns
SELECT DISTINCT
state, city
FROM
customers
WHERE
state IS NOT NULL
ORDER BY state , city;
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DISTINCT and aggregate function
SELECT
COUNT(DISTINCT state)
FROM
customers
WHERE
country = 'USA';
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Introduction to LIMIT clause
the LIMIT clause syntax with two arguments…
SELECT
column1,column2,...
FROM
table
LIMIT offset , count;
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Using LIMIT to get the first N rows
You can use the LIMIT clause to select the first N rows in a table, for example…
SELECT
customernumber, customername, creditlimit
FROM
customers
LIMIT 10;
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Using LIMIT to get the highest values
SELECT
customernumber, customername, creditlimit
FROM
customers
ORDER BY creditlimit DESC
LIMIT 5;
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Using LIMIT to get the lowest values
SELECT
customernumber, customername, creditlimit
FROM
customers
ORDER BY creditlimit ASC
LIMIT 5;
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Using LIMIT to get the lowest values
SELECT
customernumber, customername, creditlimit
FROM
customers
ORDER BY creditlimit ASC
LIMIT 5;
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BETWEEN Operator Explained
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Introduction to BETWEEN Operator
The BETWEEN operator allows you to specify a range to test. We often use the BETWEEN operator in the WHEREclause of the SELECT, INSERT, UPDATE, and DELETEstatements.
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syntax of the BETWEEN operator:
expr [NOT] BETWEEN begin_expr AND end_expr;
BETWEEN with number examples
SELECT
productCode, productName, buyPrice
FROM
products
WHERE
buyPrice BETWEEN 90 AND 100;
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BETWEEN with number examples
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BETWEEN with number examples 2
SELECT
productCode, productName, buyPrice
FROM
products
WHERE
buyPrice >= 90 AND buyPrice <= 100;
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BETWEEN with number examples 3
SELECT
productCode, productName, buyPrice
FROM
products
WHERE
buyPrice NOT BETWEEN 20 AND 100;
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BETWEEN with number examples 4
SELECT
productCode, productName, buyPrice
FROM
products
WHERE
buyPrice < 20 OR buyPrice > 100;
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Using LIKE Operator To Select Data Based
• The percentage ( % ) wildcard allows you to match any string of zero or more characters.
• The underscore ( _ ) wildcard allows you to match any single character.
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LIKE with percentage (%) wildcard
SELECT
employeeNumber, lastName, firstName
FROM
employees
WHERE
firstName LIKE 'a%';
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LIKE with percentage (%) wildcard 2
SELECT
employeeNumber, lastName, firstName
FROM
employees
WHERE
lastName LIKE '%on';
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LIKE with percentage (%) wildcard 3
SELECT
employeeNumber, lastName, firstName
FROM
employees
WHERE
lastName LIKE '%on%';
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LIKE with underscore( _ ) wildcard
SELECT
employeeNumber, lastName, firstName
FROM
employees
WHERE
firstName LIKE 'T_m';
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LIKE operator with NOT operator
SELECT
employeeNumber, lastName, firstName
FROM
employees
WHERE
lastName NOT LIKE 'B%';
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Introducing to GROUP BY clause
The following illustrates the GROUP BY clause syntax:
SELECT c1, c2,..., cn, aggregate_function(ci)
FROM table
WHERE where_conditions
GROUP BY c1 , c2,...,cn;
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Simple GROUP BY example 1
SELECT
status
FROM
orders
GROUP BY status;
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GROUP BY with aggregate functions
SELECT
status, COUNT(*)
FROM
orders
GROUP BY status;
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Simple GROUP BY example 2
SELECT
status, COUNT(*)
FROM
orders
GROUP BY status DESC;
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