Example analysis of regexp_like() function in mysql
In MySQL, the REGEXP_LIKE() function is used to determine whether a string matches a regular expression.
If the string matches the provided regular expression, the function returns 1; if it does not match, it returns 0.
Syntax:
REGEXP_LIKE(expr, pat[, match_type])
where expr is the input string and pat is the regular expression of the test string.
The optional match_type parameter allows you to refine the regular expression.
For example, you can use match_type to specify a case-sensitive match or not.
regexp_like() Example 1 - Basic usage
The following is a basic example:
SELECT REGEXP_LIKE('Cat', '.*') Result;
Result:
+--------+ | Result | +--------+ | 1 | +--------+
In this case, the regular expression specifies any character in any sequence, so of course we get a match. The function returns 1 to indicate a match.
regexp_like() Example 2 - No match
The following is an example where the input string does not match the regular expression:
SELECT REGEXP_LIKE('Cat', 'b+') Result;
Result:
+--------+ | Result | +--------+ | 0 | +--------+
In this case, the regular expression specifies that there should be one or more b characters in any sequence. Our input string does not contain this character, so 0 is returned.
regexp_like() Example 3 - Match the beginning of a string
The following is an example of a regular expression specifying that a string must begin with certain characters:
SELECT REGEXP_LIKE('Cat', '^Ca') Result;
Result:
+--------+ | Result | +--------+ | 1 | +--------+
What happens if there is no match:
SELECT REGEXP_LIKE('Cat', '^Da') Result;
Result:
+--------+ | Result | +--------+ | 0 | +--------+
regexp_like() example 4 - match_type parameter
You can provide additional parameters to determine the match type. This allows you to specify whether the match is case-sensitive, includes line terminators, etc.
The following is an example of specifying case-sensitive matching and case-sensitive matching:
SELECT REGEXP_LIKE('Cat', '^ca', 'c') 'Case-Sensitive', REGEXP_LIKE('Cat', '^ca', 'i') 'Case-Insensitive';
Result:
+----------------+------------------+ | Case-Sensitive | Case-Insensitive | +----------------+------------------+ | 0 | 1 | +----------------+------------------+
The match_type parameter can contain the following characters:
c: Case-sensitive matching.
i: Matches regardless of case.
m: Multi-line mode. Identify line terminators in strings. The default behavior is to match line terminators only at the beginning and end of a string expression.
n: The .
character matches the line terminator. The default setting is .
matches to stop at the end of the line.
u: Unix-only line endings. Only newline characters are recognized as line terminators by the .
, ^
, and $
matching operators.
Related recommendations: "mysql tutorial"
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