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Sqlite regex case insensitive11/24/2023 ![]() For example: sqlite> select Text_Value from Test where Text_Value = 'B' For example: create table TestĮxpressions involving Test.Text_Value should now be case insensitive. You can specify collate nocase when you create an index as well. WHERE name = 'someone' COLLATE NOCASEĪdditionaly, in SQLite, you can indicate that a column should be case insensitive when you create the table by specifying collate nocase in the column definition (the other options are binary (the default) and rtrim see here). REGEXP_REPLACE('Cat', 'c.You can use COLLATE NOCASE in your SELECT query: SELECT * FROM. REGEXP_REPLACE('Cat', null, 'dog') AS "2", Passing null as any argument results in null: SELECT REGEXP_REPLACE(BINARY 'My Cats', '(?-i)c.t', 'dog') AS "Binary" REGEXP_REPLACE('My Cats', '(?-i)c.t', 'dog') AS "Character", REGEXP_REPLACE(BINARY 'My Cats', 'C.t', 'dog') AS "Binary" Ĭase sensitivity on BINARY strings can also be overridden with the (?-i) and (?i) PCRE flags: SELECT REGEXP_REPLACE('My Cats', 'C.t', 'dog') AS "Character", Here’s what happens if we change the case: SELECT REGEXP_REPLACE(BINARY 'My Cats', 'c.t', 'dog') AS "Binary" REGEXP_REPLACE('My Cats', 'c.t', 'dog') AS "Character", With BINARY strings, an upper case character is different to its lower case counterpart: Passing a BINARY string also affects the case sensitivity. REGEXP_REPLACE(_latin7'My Cats' COLLATE latin7_general_cs, '(?i)c.t', 'dog') AS "Case Sensitive" REGEXP_REPLACE(_latin7'My Cats' COLLATE latin7_general_ci, '(?i)c.t', 'dog') AS "Case Insensitive", REGEXP_REPLACE('My Cats', '(?i)c.t', 'dog') AS "My Default", REGEXP_REPLACE(_latin7'My Cats' COLLATE latin7_general_cs, '(?-i)c.t', 'dog') AS "Case Sensitive" Īnd here it is using the (?i) flag to force case insensitivity: SELECT REGEXP_REPLACE(_latin7'My Cats' COLLATE latin7_general_ci, '(?-i)c.t', 'dog') AS "Case Insensitive", REGEXP_REPLACE('My Cats', '(?-i)c.t', 'dog') AS "My Default", Here’s the previous example, but this time using the (?-i) flag on each pattern to force case sensitivity: SELECT The collation case sensitivity can be overridden using the ( ?i) and ( ?-i) PCRE flags. Providing a BINARY string is also case sensitive (more on this later). The other two strings were forced to a case insensitive collation and case sensitive collation respectively. ![]() My default collation is case insensitive. | My Default | Case Insensitive | Case Sensitive | REGEXP_REPLACE(_latin7'My Cats' COLLATE latin7_general_cs, 'c.t', 'dog') AS "Case Sensitive" REGEXP_REPLACE(_latin7'My Cats' COLLATE latin7_general_ci, 'c.t', 'dog') AS "Case Insensitive", REGEXP_REPLACE('My Cats', 'c.t', 'dog') AS "My Default", Matching is performed case insensitively for case insensitive collations, and case sensitively for case sensitive collations and for binary data. The REGEXP_REPLACE() function follows the case sensitivity rules of the effective collation. There’s no match, so the original string is returned unchanged. | REGEXP_REPLACE('Cats and dogs', 't.g', 'bird') | Here’s an example where there’s no match: SELECT REGEXP_REPLACE('Cats and dogs', 't.g', 'bird') | REGEXP_REPLACE('My dog likes other dogs', 'd.g', 'bird') | Here’s an example with multiple matches: SELECT REGEXP_REPLACE('My dog likes other dogs', 'd.g', 'bird') In order to use REGEXP_REPLACE() effectively, you’ll need to know the correct pattern to use for the desired outcome. Regular expressions can be very powerful, and this example uses a very simple example. In this case there’s a match, and the substring is replaced with the replacement string. | REGEXP_REPLACE('Cats and dogs', 'd.g', 'bird') | Here’s a basic example of using REGEXP_REPLACE() in MariaDB: SELECT REGEXP_REPLACE('Cats and dogs', 'd.g', 'bird') ![]() MySQL’s version allows you to provide arguments for the starting position of the search, which occurrence to search for, as well as a way to refine the regular expression with match type. Note that, at the time of writing, MariaDB’s version of REGEXP_REPLACE() accepts fewer arguments than MySQL’s REGEXP_REPLACE() function. Where subject is the input string, pattern is the regular expression pattern for the substring, and replace is the replacement string. The syntax goes like this: REGEXP_REPLACE(subject, pattern, replace) ![]() the input string doesn’t contain the substring), the the whole string is returned unchanged. The whole string is returned along with the replacements. ![]() In MariaDB, the REGEXP_REPLACE() function replaces occurrences of the substring within a string that matches the given regular expression pattern. ![]()
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