


Laravel Eloquent: Select Rows with Maximum Created_at
In Laravel Eloquent, you may encounter scenarios where you need to select all rows with the maximum created_at value for each unique seller_id in a table. Here's how you can achieve this:
Using Raw SQL Query
One approach is to use a raw SQL query, which could be more efficient for certain circumstances:
<code class="sql">select s.* from snapshot s left join snapshot s1 on s.seller_id = s1.seller_id and s.created_at <p><strong>Using Query Builder</strong></p> <p>Alternatively, you can utilize Laravel's query builder for a more object-oriented approach:</p> <pre class="brush:php;toolbar:false"><code class="php"> DB::table('snapshot as s') ->select('s.*') ->leftJoin('snapshot as s1', function ($join) { $join->on('s.seller_id', '=', 's1.seller_id') ->whereRaw('s.created_at whereNull('s1.seller_id') ->get();</code>
Both methods will return a collection of objects representing the latest rows for each unique seller_id in the snapshot table.
The above is the detailed content of How to Select Rows with the Maximum `created_at` for Each Unique `seller_id` in Laravel Eloquent?. For more information, please follow other related articles on the PHP Chinese website!

ThebestapproachforsendingemailsinPHPisusingthePHPMailerlibraryduetoitsreliability,featurerichness,andeaseofuse.PHPMailersupportsSMTP,providesdetailederrorhandling,allowssendingHTMLandplaintextemails,supportsattachments,andenhancessecurity.Foroptimalu

The reason for using Dependency Injection (DI) is that it promotes loose coupling, testability, and maintainability of the code. 1) Use constructor to inject dependencies, 2) Avoid using service locators, 3) Use dependency injection containers to manage dependencies, 4) Improve testability through injecting dependencies, 5) Avoid over-injection dependencies, 6) Consider the impact of DI on performance.

PHPperformancetuningiscrucialbecauseitenhancesspeedandefficiency,whicharevitalforwebapplications.1)CachingwithAPCureducesdatabaseloadandimprovesresponsetimes.2)Optimizingdatabasequeriesbyselectingnecessarycolumnsandusingindexingspeedsupdataretrieval.

ThebestpracticesforsendingemailssecurelyinPHPinclude:1)UsingsecureconfigurationswithSMTPandSTARTTLSencryption,2)Validatingandsanitizinginputstopreventinjectionattacks,3)EncryptingsensitivedatawithinemailsusingOpenSSL,4)Properlyhandlingemailheaderstoa

TooptimizePHPapplicationsforperformance,usecaching,databaseoptimization,opcodecaching,andserverconfiguration.1)ImplementcachingwithAPCutoreducedatafetchtimes.2)Optimizedatabasesbyindexing,balancingreadandwriteoperations.3)EnableOPcachetoavoidrecompil

DependencyinjectioninPHPisadesignpatternthatenhancesflexibility,testability,andmaintainabilitybyprovidingexternaldependenciestoclasses.Itallowsforloosecoupling,easiertestingthroughmocking,andmodulardesign,butrequirescarefulstructuringtoavoidover-inje

PHP performance optimization can be achieved through the following steps: 1) use require_once or include_once on the top of the script to reduce the number of file loads; 2) use preprocessing statements and batch processing to reduce the number of database queries; 3) configure OPcache for opcode cache; 4) enable and configure PHP-FPM optimization process management; 5) use CDN to distribute static resources; 6) use Xdebug or Blackfire for code performance analysis; 7) select efficient data structures such as arrays; 8) write modular code for optimization execution.

OpcodecachingsignificantlyimprovesPHPperformancebycachingcompiledcode,reducingserverloadandresponsetimes.1)ItstorescompiledPHPcodeinmemory,bypassingparsingandcompiling.2)UseOPcachebysettingparametersinphp.ini,likememoryconsumptionandscriptlimits.3)Ad


Hot AI Tools

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

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

Undress AI Tool
Undress images for free

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

mPDF
mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function

SecLists
SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.

SublimeText3 English version
Recommended: Win version, supports code prompts!

PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool
