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W3schools - SQL_LIKE / Alias

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LIKE

Is used in a WHERE clause to search for a specified pattern in a column

Two wildcards often used in conjunction with the LIKE operator

  • The percent sign(%) represents zero, one, or multiple characters

  • The underscore sign(_) represents on, single character

  • Can also be used in combinations

Syntax

SELECT column1, column2, …
FROM table_name
WHERE columnN LIKE pattern;

Wild card

Is used to substitute one or more chars in a string

Symbol Desc
% Represents zero or more chars
_ Represents a single char
[] Represents any single char within the brackets
^ Represents any char not in the brackets
- Represents any single char within the specified range
Pattern Desc
‘a%’ Find values that start with “a”
‘%a’ Find values that end with “a”
‘%a%’ Find values that have “a” in any position
‘_a%’ Find values that have “a” in the second position
‘a_%’ Find values that start with “a” and are at least 2 chars in length
‘a__%’ Find values that start with “a” and are at least 3 chars in length
‘a%o’ Find values that start with “a” and ends with “o”

IN

Allows to specify multiple values in a WHERE clause

Is shorthand for multiple OR conditions

Syntax

SELECT column_name(s)
FROM table_name
WHERE column_name IN (value1,value2,…);
-- or
SELECT column_name(s)
FROM table_name
WHERE column_name IN  (SELECT STATEMENT);

BETWEEN

Selects values within a given range. The values cans be numbers, text, or dates

Is inclusive: begin and end values are included

Syntax

SELECT column_name(s)
FROM table_name
WHERE column_name BETWEEN value1 AND value2;

Alias

Is used to give a table, or a column in a table, a temporary name

Only exists for the duration of that query

Is created with the AS keyword

Syntax

SELECT column_name AS alias_name
FROM table_name;

It requires double quotation marks or square brackets if the alias name contains spaces

-- Creates an alias named “Address” that combine four columns
SELECT CustomerName, Address + ‘,’ + PostalCode + ‘ ‘ + City + ‘,’ + Country AS Address
FROM Customers;
-- Alias for tables
SELECT o.OrderID, o.OrderDate, c.CustomerName
FROM Customers AS c, Orders AS o
WHERE c.CustomerName = ‘Around the Horn’ AND c.CustomerID = o.CustormerID;