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PostgreSQL - Wildcards



The PostgreSQL wildcard character is used to specify one or more character in a string. It is used with LIKE clause and WHERE clause to search for a specified pattern.

Wildcard Characters in PostgreSQL

SymbolDescriptionExample
%Represents zero, one or multiple characters.'J%' represents a value that start with "J", for example - John, Jo and Jack etc.
_Represents one character.'_o%' represents a value that have "o" in the second position, for example - John, Jo and Journey etc.
ESCAPEAllow test for literal instances of a wildcard character such as % or _'J%!%' ESCAPE '!' represents a value that starts with J and ends in %, for example - John%, Jo% and Journey% etc.

The table below describes patterns which is used with LIKE operator and uses (%) and (_).

PatternDescription
'J%'A value that start with "J".
'%n'A value that end with "n".
'%oh%'A value that have "oh" in any position.
'_o%'A value that have "o" in the second position.
'J_%'A value that start with "J" and have at least 2 characters.
'J__%'A value that start with "J" and have at least 3 characters.
'J%n'A value that start with "J" and ends with "n".

Example:

Consider a database containing a table called Employee with the following records:

EmpIDNameCityAgeSalary
1JohnLondon253000
2MarryNew York242750
3JoParis272800
4KimAmsterdam303100
5RameshNew Delhi283000
6HuangBeijing282800

  • Using the % Wildcard : To select all records of the Employee table with Name starting with 'Jo', the query is given below.

    SELECT * FROM Employee
    WHERE Name LIKE 'Jo%';
    

    This will produce the result as shown below:

    EmpIDNameCityAgeSalary
    1JohnLondon253000
    3JoParis272800
  • Using the % Wildcard with NOT LIKE operator: NOT LIKE operator is used as the negation of LIKE operator. For example, to select all records of the Employee table with Name not starting with 'Jo', the following query can be used:

    SELECT * FROM Employee
    WHERE Name NOT LIKE 'Jo%';
    

    This will produce the result as shown below:

    EmpIDNameCityAgeSalary
    2MarryNew York242750
    4KimAmsterdam303100
    5RameshNew Delhi283000
    6HuangBeijing282800
  • Using the _ Wildcard : To select all records of the Employee table with Name containing 'o' as second character, the query is mentioned below.

    SELECT * FROM Employee
    WHERE Name LIKE '_o%';
    

    The result of the above code will be:

    EmpIDNameCityAgeSalary
    1JohnLondon253000
    3JoParis272800