10/20/2023 0 Comments Mysql like vs substring![]() In your case a firstname is more likely to be matched using LIKE than REGEXP and hence, it will be more optimized. LIKE is used to add wildcards to a string whereas REGEXP is used to match an attribute with Regular Expressions. Microsoft SQL Server has partial support of regular expression wildcards in the LIKE operator, and also a dbo.RegexMatch() function. REGEXP and LIKE are used to totally different cases. It was requested in to support SIMILAR TO syntax to help MySQL comply with the SQL standard, but the request was turned down, because it had subtly different behavior to the existing REGEXP/ RLIKE operator. select count () from ulog where logtext like 'AUT' 1 row (s) returned : 90ms taken select count () from ulog where substr (logtext,1,3)'AUT' 1 row (s) returned : 493ms taken. MySQL called the operator REGEXP and RLIKE is a synonym ( ). But since this predicate was introduced in a later edition of the SQL standard, some implementations had already developed their own solution that was almost the same. Later versions of the SQL standard introduced a new predicate SIMILAR TO which supports much richer patterns and wildcards, since the right-side operand is a string which contains a regular expression. These are not standard forms of wildcards for the LIKE predicate, and other brands of SQL database don't support them. matches one character, which must not be one of the characters in the range inside the brackets. Syntax SUBSTRINGINDEX ( string, delimiter, number) Parameter Values Technical Details Works in: From MySQL 4. The - is a range operator, unless it appears at the start or end of the string inside the brackets. Definition and Usage The SUBSTRINGINDEX () function returns a substring of a string before a specified number of delimiter occurs. matches one character, but only characters in the range inside the brackets. They support % and _ wildcards, and the \ escape character, but they extend standard SQL with two other forms: Microsoft SQL Server's LIKE syntax is documented here: put a backslash before it: WHERE title LIKE 'The 7\% Solution' in regular expressions.Īlso if you want to match a literal '%' or '_', you need to escape it, i.e. % matches zero or more of any characters. These are the only wildcards an SQL product needs to support if they want to say they are SQL compliant and support the LIKE predicate. ![]() Standard SQL from decades ago defined only two wildcards: % and _.
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