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

Question

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.

Answer 1

我总是使用lower解决这个问题：

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

Answer 2

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 '%'

Answer 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 .

Answer 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>%')

Answer 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

Answer 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();

Answer 7

我认为此查询将进行不区分大小写的搜索：

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

Answer 8

use ILIKE

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

it worked for me !!

Answer 9

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;

Answer 10

非二进制字符串比较（包括LIKE ）在 MySql 中默认不区分大小写： https : //dev.mysql.com/doc/refman/en/case-sensitive.html

Answer 11

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 :)

Answer 12

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

Answer 13

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

Answer 14

当我想开发不敏感的大小写搜索时，我总是在比较之前将每个字符串转换为小写

Answer 15

我一直是这样解决的：

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

Answer 16

You can use the following method

 private function generateStringCondition($value = '',$field = '', $operator = '', $regex = '', $wildcardStart = '', $wildcardEnd = ''){
        if($value != ''){
            $where = " $field $regex '$wildcardStart".strtolower($value)."$wildcardEnd' ";

            $searchArray = explode(' ', $value);

            if(sizeof($searchArray) > 1){

                foreach ($searchArray as $key=>$value){
                    $where .="$operator $field $regex '$wildcardStart".strtolower($value)."$wildcardEnd'";
                }

            }

        }else{
            $where = '';
        }
        return $where;
    }

use this method like below

   $where =  $this->generateStringCondition($yourSearchString,  'LOWER(columnName)','or', 'like',  '%', '%');
  $sql = "select * from table $where";