Showing posts with label SQL Wildcards. Show all posts
Showing posts with label SQL Wildcards. Show all posts

Friday, July 22, 2011

SQL Wildcards


SQL wildcards can be used when searching for data in a database.

SQL Wildcards 

SQL wildcards can substitute for one or more characters when searching for data in a database.
SQL wildcards must be used with the SQL LIKE operator.
With SQL, the following wildcards can be used:
WildcardDescription
%A substitute for zero or more characters
_A substitute for exactly one character
[charlist]Any single character in charlist
[^charlist]
or
[!charlist]
Any single character not in charlist


SQL Wildcard Examples

We have the following "Persons" table:
P_IdLastNameFirstNameAddressCity
1HansenOlaTimoteivn 10Sandnes
2SvendsonToveBorgvn 23Sandnes
3PettersenKariStorgt 20Stavanger


Using the % Wildcard

Now we want to select the persons living in a city that starts with "sa" from the "Persons" table.
We use the following SELECT statement:
SELECT * FROM Persons
WHERE City LIKE 'sa%'
The result-set will look like this:
P_IdLastNameFirstNameAddressCity
1HansenOlaTimoteivn 10Sandnes
2SvendsonToveBorgvn 23Sandnes
Next, we want to select the persons living in a city that contains the pattern "nes" from the "Persons" table.
We use the following SELECT statement:
SELECT * FROM Persons
WHERE City LIKE '%nes%'
The result-set will look like this:
P_IdLastNameFirstNameAddressCity
1HansenOlaTimoteivn 10Sandnes
2SvendsonToveBorgvn 23Sandnes


Using the _ Wildcard

Now we want to select the persons with a first name that starts with any character, followed by "la" from the "Persons" table.
We use the following SELECT statement:
SELECT * FROM Persons
WHERE FirstName LIKE '_la'
The result-set will look like this:
P_IdLastNameFirstNameAddressCity
1HansenOlaTimoteivn 10Sandnes
Next, we want to select the persons with a last name that starts with "S", followed by any character, followed by "end", followed by any character, followed by "on" from the "Persons" table.
We use the following SELECT statement:
SELECT * FROM Persons
WHERE LastName LIKE 'S_end_on'
The result-set will look like this:
P_IdLastNameFirstNameAddressCity
2SvendsonToveBorgvn 23Sandnes


Using the [charlist] Wildcard

Now we want to select the persons with a last name that starts with "b" or "s" or "p" from the "Persons" table.
We use the following SELECT statement:
SELECT * FROM Persons
WHERE LastName LIKE '[bsp]%'
The result-set will look like this:
P_IdLastNameFirstNameAddressCity
2SvendsonToveBorgvn 23Sandnes
3PettersenKariStorgt 20Stavanger
Next, we want to select the persons with a last name that do not start with "b" or "s" or "p" from the "Persons" table.
We use the following SELECT statement:
SELECT * FROM Persons
WHERE LastName LIKE '[!bsp]%'
The result-set will look like this:
P_IdLastNameFirstNameAddressCity
1HansenOlaTimoteivn 10Sandnes

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