


Why Am I Getting Null Results When Using PHP PDO Prepared Statements with MySQL LIKE Queries?
Oct 30, 2024 pm 07:11 PMPHP PDO Prepared Statement MySQL LIKE Query: Resolve Null Results
In MySQL, a common operation involves querying data using a LIKE clause to perform wildcard searches. When using PHP's PDO class with MySQL, it's essential to understand how to correctly craft these queries to avoid null results.
Let's examine a scenario where a LIKE query is not returning results through the PDO class. The original query in the MySQL client is:
<code class="sql">SELECT hs.hs_pk, hs.hs_text, hs.hs_did, hd.hd_did, hd.hd_text, hv.hv_text, hc.hc_text FROM hs LEFT JOIN hd ON hs.hs_did = hd.hd_did LEFT JOIN hd ON hd.hd_vid = hv.hv_id LEFT JOIN hc ON hd.hd_pclass = hc.hc_id WHERE hs.hs_text LIKE "%searchTerm%" LIMIT 25;</code>
This query leverages the LIKE operator to find all rows where the hs.hs_text column contains the searchTerm within its value. However, when this query is translated into PHP's PDO class, it fails to return any results.
<code class="php">$sql = 'SELECT hs.hs_pk, hs.hs_text, hs.hs_did, hd.hd_did, hd.hd_text, hv.hv_text, hc.hc_text FROM hs LEFT JOIN hd ON hs.hs_did = hd.hd_did LEFT JOIN hd ON hd.hd_vid = hv.hv_id LEFT JOIN hc ON hd.hd_pclass = hc.hc_id WHERE hs.hs_text LIKE :searchTerm LIMIT 25'; $ret = $prep->execute(array(':searchTerm' => '"%'.$searchTerm.'%"'));</code>
The issue in the PHP code is the presence of double quotes around the searchTerm in the WHERE clause. Prepared statements in PHP do not require quotes when binding values. Quotes are only needed when string values are directly embedded into the query itself.
To resolve the issue, simply remove the double quotes from the searchTerm parameter:
<code class="php">$ret = $prep->execute(array(':searchTerm' => '%'.$searchTerm.'%'));</code>
This modification allows the PDO class to correctly bind the searchTerm value to the query, which will produce the expected results.
Prepared statements provide increased security and efficiency by separating data from the query. They prevent SQL injection vulnerabilities and optimize query execution by allowing the database to handle the binding process. Understanding how to correctly use LIKE queries with PHP's PDO class is essential for effective data retrieval from MySQL databases.
The above is the detailed content of Why Am I Getting Null Results When Using PHP PDO Prepared Statements with MySQL LIKE Queries?. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undress AI Tool
Undress images for free

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics

TosecurelyhandleauthenticationandauthorizationinPHP,followthesesteps:1.Alwayshashpasswordswithpassword_hash()andverifyusingpassword_verify(),usepreparedstatementstopreventSQLinjection,andstoreuserdatain$_SESSIONafterlogin.2.Implementrole-basedaccessc

To safely handle file uploads in PHP, the core is to verify file types, rename files, and restrict permissions. 1. Use finfo_file() to check the real MIME type, and only specific types such as image/jpeg are allowed; 2. Use uniqid() to generate random file names and store them in non-Web root directory; 3. Limit file size through php.ini and HTML forms, and set directory permissions to 0755; 4. Use ClamAV to scan malware to enhance security. These steps effectively prevent security vulnerabilities and ensure that the file upload process is safe and reliable.

In PHP, the main difference between == and == is the strictness of type checking. ==Type conversion will be performed before comparison, for example, 5=="5" returns true, and ===Request that the value and type are the same before true will be returned, for example, 5==="5" returns false. In usage scenarios, === is more secure and should be used first, and == is only used when type conversion is required.

The methods of using basic mathematical operations in PHP are as follows: 1. Addition signs support integers and floating-point numbers, and can also be used for variables. String numbers will be automatically converted but not recommended to dependencies; 2. Subtraction signs use - signs, variables are the same, and type conversion is also applicable; 3. Multiplication signs use * signs, which are suitable for numbers and similar strings; 4. Division uses / signs, which need to avoid dividing by zero, and note that the result may be floating-point numbers; 5. Taking the modulus signs can be used to judge odd and even numbers, and when processing negative numbers, the remainder signs are consistent with the dividend. The key to using these operators correctly is to ensure that the data types are clear and the boundary situation is handled well.

Yes, PHP can interact with NoSQL databases like MongoDB and Redis through specific extensions or libraries. First, use the MongoDBPHP driver (installed through PECL or Composer) to create client instances and operate databases and collections, supporting insertion, query, aggregation and other operations; second, use the Predis library or phpredis extension to connect to Redis, perform key-value settings and acquisitions, and recommend phpredis for high-performance scenarios, while Predis is convenient for rapid deployment; both are suitable for production environments and are well-documented.

TostaycurrentwithPHPdevelopmentsandbestpractices,followkeynewssourceslikePHP.netandPHPWeekly,engagewithcommunitiesonforumsandconferences,keeptoolingupdatedandgraduallyadoptnewfeatures,andreadorcontributetoopensourceprojects.First,followreliablesource

PHPbecamepopularforwebdevelopmentduetoitseaseoflearning,seamlessintegrationwithHTML,widespreadhostingsupport,andalargeecosystemincludingframeworkslikeLaravelandCMSplatformslikeWordPress.Itexcelsinhandlingformsubmissions,managingusersessions,interacti

TosettherighttimezoneinPHP,usedate_default_timezone_set()functionatthestartofyourscriptwithavalididentifiersuchas'America/New_York'.1.Usedate_default_timezone_set()beforeanydate/timefunctions.2.Alternatively,configurethephp.inifilebysettingdate.timez
