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When searching for data in the database, you can use SQL wildcards. This article will explain the relevant knowledge in detail.
You can use SQL wildcards when searching for data in a database.
SQL Wildcards
SQL wildcards can replace one or more characters when searching for data in a database.
SQL wildcards must be used with the LIKE operator.
In SQL, you can use the following wildcards:
Use the % wildcard character
Example 1
Now, we want to extract data from the "Persons" table above Select people living in cities starting with "Ne":
We can use the following SELECT statement:
SELECT * FROM Persons WHERE City LIKE 'Ne%'
Example 2
Next, we want to start with " Persons" table to select people living in cities containing "lond":
We can use the following SELECT statement:
SELECT * FROM Persons WHERE City LIKE '%lond%'
Use _ wildcard
Example 1
Now, we want to select people whose first character is "eorge" after the first character of their name from the above "Persons" table:
We can use the following SELECT statement:
SELECT * FROM Persons WHERE FirstName LIKE '_eorge'
Example 2
Next, we want the last name of this record selected from the "Persons" table to start with "C", then any character, then "r", then any character, then "er":
We can use the following SELECT statement:
SELECT * FROM Persons WHERE LastName LIKE 'C_r_er'
Use [charlist] wildcard
Example 1
Now, we want to select people whose cities start with "A" or "L" or "N" from the "Persons" table above:
We can use the following SELECT statement :
SELECT * FROM Persons WHERE City LIKE '[ALN]%'
Example 2
Now, we want to select people whose cities do not start with "A" or "L" or "N" from the "Persons" table above:
We can use the following SELECT statement:
SELECT * FROM Persons WHERE City LIKE '[!ALN]%'
This article provides a relevant explanation of wildcards. For more learning materials, please pay attention to the php Chinese website.
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