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  • SQL通配符

    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:

    Wildcard Description
    % 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_Id LastName FirstName Address City
    1 Hansen Ola Timoteivn 10 Sandnes
    2 Svendson Tove Borgvn 23 Sandnes
    3 Pettersen Kari Storgt 20 Stavanger


    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_Id LastName FirstName Address City
    1 Hansen Ola Timoteivn 10 Sandnes
    2 Svendson Tove Borgvn 23 Sandnes

    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_Id LastName FirstName Address City
    1 Hansen Ola Timoteivn 10 Sandnes
    2 Svendson Tove Borgvn 23 Sandnes


    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_Id LastName FirstName Address City
    1 Hansen Ola Timoteivn 10 Sandnes

    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_Id LastName FirstName Address City
    2 Svendson Tove Borgvn 23 Sandnes


    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_Id LastName FirstName Address City
    2 Svendson Tove Borgvn 23 Sandnes
    3 Pettersen Kari Storgt 20 Stavanger

    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_Id LastName FirstName Address City
    1 Hansen Ola Timoteivn 10 Sandnes

    原文地址:http://www.w3schools.com/SQL/sql_wildcards.asp

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  • 原文地址:https://www.cnblogs.com/awpatp/p/1635858.html
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