How can I search (case-insensitive) in a column using LIKE wildcard?

问题

I looked around some and didn\'t find what I was after so here goes.

SELECT * FROM trees WHERE trees.`title` LIKE  \'%elm%\'

This works fine, but not if the tree is named Elm or ELM etc...

How do I make SQL case insensitive for this wild-card search?

I\'m using MySQL 5 and Apache.

回答1:

SELECT  *
FROM    trees
WHERE   trees.`title` COLLATE UTF8_GENERAL_CI LIKE '%elm%'

Actually, if you add COLLATE UTF8_GENERAL_CI to your column's definition, you can just omit all these tricks: it will work automatically.

ALTER TABLE trees 
 MODIFY COLUMN title VARCHAR(…) CHARACTER 
 SET UTF8 COLLATE UTF8_GENERAL_CI.

This will also rebuild any indexes on this column so that they could be used for the queries without leading '%'

回答2:

I've always solved this using lower:

SELECT * FROM trees WHERE LOWER( trees.title ) LIKE  '%elm%'

回答3:

The case sensitivity is defined in the columns / tables / database collation settings. You can do the query under a specific collation in the following way:

SELECT *
FROM trees
WHERE trees.`title` LIKE '%elm%' COLLATE utf8_general_ci

for instance.

(Replace utf8_general_ci with whatever collation you find useful). The _ci stands for case insensitive.

回答4:

This is the example of a simple LIKE query:

SELECT * FROM <table> WHERE <key> LIKE '%<searchpattern>%'

Now, case-insensitive using LOWER() func:

SELECT * FROM <table> WHERE LOWER(<key>) LIKE LOWER('%<searchpattern>%')

回答5:

Simply use :

"SELECT * FROM `trees` WHERE LOWER(trees.`title`) LIKE  '%elm%'";

Or Use

"SELECT * FROM `trees` WHERE LCASE(trees.`title`) LIKE  '%elm%'";

Both functions works same

回答6:

I'm doing something like that.

Getting the values in lowercase and MySQL does the rest

    $string = $_GET['string'];
    mysqli_query($con,"SELECT *
                       FROM table_name
                       WHERE LOWER(column_name)
                       LIKE LOWER('%$string%')");

And For MySQL PDO Alternative:

        $string = $_GET['string'];
        $q = "SELECT *
              FROM table_name
              WHERE LOWER(column_name)
              LIKE LOWER(?);";
        $query = $dbConnection->prepare($q);
        $query->bindValue(1, "%$string%", PDO::PARAM_STR);
        $query->execute();

回答7:

I think this query will do a case insensitive search:

SELECT * FROM trees WHERE trees.`title` ILIKE '%elm%';

回答8:

You don't need to ALTER any table. Just use the following queries, prior to the actual SELECT query that you want to use the wildcard:

    set names `utf8`;
    SET COLLATION_CONNECTION=utf8_general_ci;
    SET CHARACTER_SET_CLIENT=utf8;
    SET CHARACTER_SET_RESULTS=utf8;

回答9:

well in mysql 5.5 , like operator is insensitive...so if your vale is elm or ELM or Elm or eLM or any other , and you use like '%elm%' , it will list all the matching values.

I cant say about earlier versions of mysql.

If you go in Oracle , like work as case-sensitive , so if you type like '%elm%' , it will go only for this and ignore uppercases..

Strange , but this is how it is :)

回答10:

SELECT name 
       FROM gallery 
       WHERE CONVERT(name USING utf8) LIKE _utf8 '%$q%' 
       GROUP BY name COLLATE utf8_general_ci LIMIT 5

回答11:

You must set up proper encoding and collation for your tables.

Table encoding must reflect the actual data encoding. What is your data encoding?

To see table encoding, you can run a query SHOW CREATE TABLE tablename

回答12:

When I want to develop insensitive case searchs, I always convert every string to lower case before do comparasion

回答13:

use ILIKE

SELECT * FROM trees WHERE trees.`title` ILIKE '%elm%';

it worked for me !!

来源：https://stackoverflow.com/questions/2876789/how-can-i-search-case-insensitive-in-a-column-using-like-wildcard

标签

mysql

sql

sql-like

case-insensitive