sql standard for like operator code example

Example 1: like sql

WHERE CustomerName LIKE 'a%'	
--Finds any values that start with "a"
WHERE CustomerName LIKE '%a'	
--Finds any values that end with "a"
WHERE CustomerName LIKE '%or%'	
--Finds any values that have "or" in any position
WHERE CustomerName LIKE '_r%'	
--Finds any values that have "r" in the second position
WHERE CustomerName LIKE 'a__%'	
--Finds any values that start with "a" and are at least 3 characters in length
WHERE ContactName LIKE 'a%o'	
--Finds any values that start with "a" and ends with "o"

Example 2: like in sql

(Like) Operator for partial searches using wildcard '%' and '_'
For Example:
Select * From Employees
Where last_name LIKE '_a%';

Example 3: sql where value like a or b

-- example
SELECT Id, ProductName, UnitPrice, Package
  FROM Product
 WHERE ProductName LIKE 'Cha_' OR ProductName LIKE 'Chan_'