


How to Concatenate Multiple Rows into a Comma-Separated List in SQL Server and Oracle?
Aggregating Multiple SQL Rows into a Single Comma-Delimited Column
This article demonstrates how to consolidate multiple rows sharing a common identifier into a single row with a comma-separated list in a specific column. The example uses a table with ticket IDs and associated individuals, aiming to create a result where each ticket ID is linked to a list of all involved individuals.
SQL Server Approach (2005 and later)
The following SQL Server query achieves this using STUFF()
, ISNULL()
, and FOR XML PATH
:
SELECT t.TicketID, STUFF(ISNULL((SELECT ', ' + x.Person FROM @Tickets x WHERE x.TicketID = t.TicketID GROUP BY x.Person FOR XML PATH (''), TYPE).value('.','VARCHAR(max)'), ''), 1, 2, '') [No Preceeding Comma], ISNULL((SELECT ', ' + x.Person FROM @Tickets x WHERE x.TicketID = t.TicketID GROUP BY x.Person FOR XML PATH (''), TYPE).value('.','VARCHAR(max)'), '') [Preceeding Comma If Not Empty] FROM @Tickets t GROUP BY t.TicketID
This query employs a subquery to gather individuals associated with each TicketID
. The FOR XML PATH
method transforms the result into a concatenated string, and STUFF()
removes any leading comma. The ISNULL()
function handles cases where no individuals are associated with a ticket. The optional columns provide flexibility in handling leading commas.
Oracle Solution
Oracle offers a more concise solution using the LISTAGG()
function:
SELECT TicketID, LISTAGG(Person, ',') WITHIN GROUP (ORDER BY Person) OVER (PARTITION BY TicketID) AS People FROM @Tickets
LISTAGG()
directly aggregates values into a comma-separated list, ordered by the Person
column. The PARTITION BY
clause ensures aggregation occurs for each distinct TicketID
. This method is significantly simpler and more efficient than the SQL Server equivalent.
The above is the detailed content of How to Concatenate Multiple Rows into a Comma-Separated List in SQL Server and Oracle?. For more information, please follow other related articles on the PHP Chinese website!

MySQLdiffersfromotherSQLdialectsinsyntaxforLIMIT,auto-increment,stringcomparison,subqueries,andperformanceanalysis.1)MySQLusesLIMIT,whileSQLServerusesTOPandOracleusesROWNUM.2)MySQL'sAUTO_INCREMENTcontrastswithPostgreSQL'sSERIALandOracle'ssequenceandt

MySQL partitioning improves performance and simplifies maintenance. 1) Divide large tables into small pieces by specific criteria (such as date ranges), 2) physically divide data into independent files, 3) MySQL can focus on related partitions when querying, 4) Query optimizer can skip unrelated partitions, 5) Choosing the right partition strategy and maintaining it regularly is key.

How to grant and revoke permissions in MySQL? 1. Use the GRANT statement to grant permissions, such as GRANTALLPRIVILEGESONdatabase_name.TO'username'@'host'; 2. Use the REVOKE statement to revoke permissions, such as REVOKEALLPRIVILEGESONdatabase_name.FROM'username'@'host' to ensure timely communication of permission changes.

InnoDB is suitable for applications that require transaction support and high concurrency, while MyISAM is suitable for applications that require more reads and less writes. 1.InnoDB supports transaction and bank-level locks, suitable for e-commerce and banking systems. 2.MyISAM provides fast read and indexing, suitable for blogging and content management systems.

There are four main JOIN types in MySQL: INNERJOIN, LEFTJOIN, RIGHTJOIN and FULLOUTERJOIN. 1.INNERJOIN returns all rows in the two tables that meet the JOIN conditions. 2.LEFTJOIN returns all rows in the left table, even if there are no matching rows in the right table. 3. RIGHTJOIN is contrary to LEFTJOIN and returns all rows in the right table. 4.FULLOUTERJOIN returns all rows in the two tables that meet or do not meet JOIN conditions.

MySQLoffersvariousstorageengines,eachsuitedfordifferentusecases:1)InnoDBisidealforapplicationsneedingACIDcomplianceandhighconcurrency,supportingtransactionsandforeignkeys.2)MyISAMisbestforread-heavyworkloads,lackingtransactionsupport.3)Memoryengineis

Common security vulnerabilities in MySQL include SQL injection, weak passwords, improper permission configuration, and unupdated software. 1. SQL injection can be prevented by using preprocessing statements. 2. Weak passwords can be avoided by forcibly using strong password strategies. 3. Improper permission configuration can be resolved through regular review and adjustment of user permissions. 4. Unupdated software can be patched by regularly checking and updating the MySQL version.

Identifying slow queries in MySQL can be achieved by enabling slow query logs and setting thresholds. 1. Enable slow query logs and set thresholds. 2. View and analyze slow query log files, and use tools such as mysqldumpslow or pt-query-digest for in-depth analysis. 3. Optimizing slow queries can be achieved through index optimization, query rewriting and avoiding the use of SELECT*.


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

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

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),

MinGW - Minimalist GNU for Windows
This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.

MantisBT
Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

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