Mysql distinct. Here we show, How to write Distinct rows.

Mysql distinct. There are the sometimes the same values, but with different The problem is that the columns used in the ORDER BY aren't specified in the DISTINCT. In other words, use JSON only to store and fetch the whole JSON document verbatim. Whether you’re analyzing customer data, generating reports, or cleaning up a dataset, DISTINCT helps you focus on what’s unique without wading through repetitive entries. Here we discuss an introduction to MySQL DISTINCT, how does it work with query examples for better understanding. If you do not use columns from all Jul 24, 2018 · What is SQL DISTINCT? DISTINCT is a keyword in SQL that allows you to show unique or distinct results. The DISTINCT can comes only once in a given select statement. Sep 24, 2009 · If you are trying to improve performance, you could try creating a persisted computed column on either a hash or concatenated value of the two columns. It’s added to a SELECT query to eliminate duplicates in the data it displays because columns often contain duplicate values and sometimes you may only want to show unique or distinct values. 2. Sep 15, 2025 · 文章浏览阅读509次，点赞14次，收藏10次。即distinct来返回不重复字段的条数（count (distinct id)）,结果如下：【实际包含null项有4个记录，执行语句后过滤null项，计算为3】其原因是distinct只能返回他的目标字段，而无法返回其他字段。对多个字段去重，表示选取多个字段拼接的一条记录，不重复的所有 May 20, 2021 · The words UNIQUE and DISTINCT are considered synonyms in our day-to-day life – but not in SQL! Find out why in this article. Ineed to find unique values in mysql table column. Below are some basic examples that demonstrate how the SQL DISTINCT clause works. If you do not use columns from all MySQL Select Distinct retrieves unique rows (by removing duplicate rows) from the specified Column. 15, “GROUP BY Optimization”. 简约的目录 01 distinct 的用法1. drugclass, rx. For example, if you want to know when your animals were born, select the name and birth columns: May 26, 2025 · When DISTINCT and UNION are used together in SQL, it's important to note that UNION by default already removes duplicate rows, similar to DISTINCT. To avoid this, you can add DISTINCT to the SELECT query. Even though their purpose is the same, they are used in various ways and they also function differently. Learn to remove duplicates from your query results effectively. This SQL tutorial explains how to use the SQL DISTINCT clause with syntax and examples. However, in MySQL even a DISTINCT + ORDER BY might still be faster than a GROUP BY due to the extra hints for the optimizer as explained by SquareCog. I just want to display all row numbers of unique (distinct) values in a column & so I tried: SELECT DISTINCT id, ROW_NUMBER() OVER (ORDER BY id) AS I have the problem, that MSSQL Server 2000 should select some distinct values from a table (the specific column is of the nvarchar type). If you do not use columns from all DISTINCT in MySQL: In MySQL, the DISTINCT clause is used with the SELECT statement to retrieve the unique records from the result set. Apr 5, 2011 · I want to retrieve the records with IDs 4, 7, 8, and 9 i. Therefore, using DISTINCT with UNION is usually redundant. Selecting a distinct date by day only from datetime (YYYY-MM-DD HH:MM:SS) in MySQL Asked 12 years, 7 months ago Modified 5 years, 1 month ago Viewed 55k times test1 test2 test3 test4 the problem here is that the string "test1 test3" is duplicated and is inserted only once, but all of the others are distinct to each other ("test1 test2 test3" is distinct than "test1 test3", even if some tests contained in the whole string are duplicated). With the use of sql DISTINCT clause data redundancy will be stop. It ensures data accuracy and is often used with the SELECT statement for clean, precise reporting. Jul 7, 2024 · Conclusion The DISTINCT clause is used for retrieving unique values from a column or combination of columns in MySQL. It is particularly useful when you want to eliminate duplicate rows from the result set. Also discussed example on MySQL GROUP_CONCAT() function, GROUP_CONCAT() with order by and example, GROUP_CONCAT() with distinct, GROUP_CONCAT() with separator. The following SQL statement selects only the DISTINCT values from the "Country" column in the "Customers" table: Jun 16, 2009 · SELECTING DISTINCT PRODUCT AND DISPLAY COUNT PER PRODUCT for another answer about this type of question, this is my way of getting the count of product based on their product name using distinct. Getting non-duplicated data enables accurate analytics and eliminates misleading aggregates when performing counts, sums, averages and more. Redundancy is the repetition of certain data in a table which can be avoided with sql select distinct clause. 0, the parser rules for SELECT and UNION were refactored to be more consistent (the same SELECT syntax applies uniformly in each such context) and reduce duplication. Master SQL techniques for unique data analysis with multiple columns and aggregate functions. Aug 12, 2017 · How can I ignore the is_enrolled field from distinct? This is the query: select DISTINCT `courses`. In this tutorial, you will learn how to use the MySQL DISTINCT clause in the SELECT statement to eliminate duplicate rows in a result set. Please note it is not just columns, but the entire record (the whole row). This article describes how to remove duplicate rows in the result using MySQL DISTINCT keyword. This will bring you the maximum ID with the correspondent data, you can use min or any other functions and you replicate that function to the sub-queries. Try something like this: SELECT DISTINCT Category, MAX(CreationDate) FROM MonitoringJob GROUP BY Category ORDER BY MAX(CreationDate) DESC, Category Feb 24, 2009 · The definition of DISTINCT and GROUP BY differ in that DISTINCT doesn't have to sort the output, and GROUP BY by default does. The examples in this article are based on the Baeldung University Aug 31, 2022 · Summary: in this tutorial, you will learn how to use the MySQL DISTINCT clause in the SELECT statement to eliminate duplicate rows in a result set. When combining LIMIT row_count with DISTINCT, MySQL stops as soon as it finds row_count unique rows. 0. 1 错误使用 distinct (c)2. Apr 14, 2023 · As predicted, adding the DISTINCT keyword removed all but one instance of NULLs : Final Thoughts on Selecting Distinct Values From a Relational Database In this blog article, we learned how to use the SQL DISTINCT clause, which removes duplicates from the result set of a SELECT statement, leaving only unique values. The outer query is needed, otherwise the distinct would not be applied. See examples, syntax, demo database and video tutorial. Sep 10, 2008 · SELECT DISTINCT a,b,c FROM t is roughly equivalent to: SELECT a,b,c FROM t GROUP BY a,b,c It's a good idea to get used to the GROUP BY syntax, as it's more powerful. In MySQL, you can obtain the number of distinct expression combinations that do not contain NULL by giving a list of expressions. It ignores all the duplicates values present in the particular column (s) and returns only the distinct values. Master using the DISTINCT in SQL with our tutorial. Jan 25, 2024 · Introduction In MySQL, retrieving distinct rows from a table is essential for various analytical tasks, such as counting the number of unique visitors on a website, or simplifying results to avoid data redundancy. The SQL SELECT DISTINCT statement retrieve the unique records, by removing the duplicates from the specified Column in the SELECT Statement. If you do not use columns from all tables named in a query, MySQL stops scanning any unused tables as soon as it finds the first match. GeeksforGeeks | A computer science portal for geeks Due to this equivalence, the optimizations applicable to GROUP BY queries can be also applied to queries with a DISTINCT clause. Compared to MySQL 5. Thus, for more details on the optimization possibilities for DISTINCT queries, see Section 10. Dec 4, 2024 · Learn how to use the SQL DISTINCT keyword to remove duplicate records from your datasets. 0 Compared to MySQL 5. By doing so, all redundancies are removed. SQL SELECT DISTINCT 语句 SELECT DISTINCT 语句用于返回唯一不同的值。 在表中，一个列可能会包含多个重复值，有时您也许希望仅仅列出不同（distinct）的值。 Mar 8, 2011 · I tried to formulate a query like so SELECT DISTINCT CAST(`date_posted` AS DATE) AS dateonly FROM table This gives me dates but they're not distinct and have duplicates. SQL SELECT column FROM table WHERE column is unique SELECT column FROM table WHERE column = DISTINCT I'v Sep 24, 2023 · Setting Up Your First Query with Select Distinct Diving right into the nitty-gritty of SQL, let’s start by setting up your first query using the SELECT DISTINCT statement. The MySQL DISTINCT clause is used to remove duplicates from the result set. 1. UNION combines the result from multiple query blocks into a single result set. In standard SQL, you would have to do a concatenation of all expressions inside COUNT(DISTINCT ). In this tutorial, we’ll learn how to combine DISTINCT and COUNT in an SQL query. saleprice=T Feb 19, 2025 · The DISTINCT keyword in MySQL is an essential tool that helps eliminate duplicate rows from your result set. name, t. Nov 4, 2022 · SQL Distinct with SQL select statement, on one column and on multiple columns, difference between SQL Distinct and Group By clause and SQL Distinct with SQL Unique constrain and SQL distinct with Order By has explained with Practical examples Feb 2, 2023 · This article will show the commonly used scenarios of SQL Select Distinct in an easily understandable format. Explore examples and best practices. In SQL, the SELECT DISTINCT statement is used to retrieve unique values from a column in a table. Learn more in this article. Feb 26, 2025 · SQL SELECT DISTINCT can be used to remove duplicate results from your queries. See the following sections covering the individual operators for more information and examples. *, IF(course_enrollments. Do not expect to use SQL operations to search, sort, or aggregate elements of JSON documents as if they were discrete relational data. Due to this equivalence, the optimizations applicable to GROUP BY queries can be also applied to queries with a DISTINCT clause. Oct 24, 2012 · mysql distinct row or distinct field Asked 12 years, 11 months ago Modified 12 years, 11 months ago Viewed 17k times This tutorial shows you how to use the SQL Server SELECT DISTINCT clause to retrieve the only distinct values in a specified list of columns. Syntax Here's the basic syntax of the SELECT DISTINCT statement: SELECT DISTINCT column1, column2, FROM table_name; The complete guide to SQL DISTINCT. However, within these columns, there may be duplicate rows. . What I have highlighted is simply an example of what I'm trying to achieve, as this table is going to eventually contain millions of records, and hundreds of individual code values. If you do not use columns from all EXCEPT limits the result from the first query block to those rows which are (also) not found in the second. May 14, 2024 · SQL distinct is used to avoide Redundancy. All three set operators also support a DISTINCT keyword, which suppresses duplicates in the result Sep 26, 2020 · 概要 SQL の DISTINCT を使うサンプルを書く 環境: MySQL Ver 8. Dec 16, 2015 · In my table I have several duplicates. drugname) AS drugCountsInFamilies I need to run a select statement that returns all rows where the value of a column is not distinct (e. I want to use DISTINCT and TOP in the same query. Learn the syntax, parameters, use cases and find practical examples in the Hightouch SQL Dictionary. com Sep 23, 2019 · Or if you want to use SQL operations like DISTINCT on the values, then store each value in a separate row. For example, if the table looks like below: CustomerName EmailAddress A Nov 19, 2014 · The SQL DISTINCT keyword is used in conjunction with a SELECT statement to eliminate all the duplicate records and fetching only unique records. As with UNION and INTERSECT, either query block can make use of any of SELECT, TABLE, or VALUES. Specifically, the accuracy and integrity of the aggregated results both rely on the uniqueness of rows when summing. Nov 7, 2023 · I have this query that runs very slowly when DISTINCT is used; SELECT COUNT (*) FROM (SELECT DISTINCT query_text FROM search_query WHERE (store_id IN (1)) AND (num_results > 0) ORDER BY popularit Oct 19, 2013 · The accepted answer does not properly handle diacritics and other non ascii characters, based on a comment by ishmael, this is my preferred way (which handles these cases correctly): SELECT DISTINCT NAME COLLATE latin1_bin FROM X; You can of course add a where clause (or any other normal SQL stuff) to restrict the results. If, for example, you have multiple identical values for first name, but the last name and other information in the selected columns is different, the record will be included in the result set. Feb 23, 2023 · Learn about the SELECT DISTINCT SQL command to return a unique list of values from SELECT queries along with several examples. For your query, I'd do it like this: UPDATE sales SET status='ACTIVE' WHERE id IN ( SELECT id FROM sales S INNER JOIN ( SELECT saleprice, saledate FROM sales GROUP BY saleprice, saledate HAVING COUNT(*) = 1 ) T ON S. Here's an example DISTINCT SQL query used to find only unique names of pharmaceutical manufacturers: When combining LIMIT row_count with DISTINCT, MySQL stops as soon as it finds row_count unique rows. May 15, 2025 · In SQL, summing distinct rows is essential when working with datasets containing duplicate entries that may arise from joins or redundant data. When the ALL keyword follows a set operator, this causes duplicates to be included in the result. The examples are based on the Baeldung University schema and are compatible with UNION Handing in MySQL 8. Explore what it is and how to use distinct in SQL in different ways here. Feb 5, 2022 · A JSON_ARRAYAGG DISTINCT returns a JSON array composed of all the different (unique) values for string-expr in the selected rows: JSON_ARRAYAGG (DISTINCT col1). The SQL Server (Transact-SQL) DISTINCT clause is used to remove duplicates from the result set. Getting distinct list of records based on the MAX of a column Ask Question Asked 12 years ago Modified 8 years ago Jan 10, 2018 · distinct这个关键字来过滤掉多余的重复记录只保留一条，但往往只用它来返回不重复记录的条数，而不是用它来返回不重记录的所有值。其原因是distinct只能返回它的目标字段，而无法返回其它字段，接下来通过本篇文章给大家分享SQL中distinct的用法，需要的朋友可以参考下 0 If you are using T-SQL, it is directly possible to use a window function by using APPROX_COUNT_DISTINCT, so for example: APPROX_COUNT_DISTINCT(rx. Sep 19, 2024 · For various analyses and reports, it can be helpful to get a list of only the unique rows from a table. Conversely, GROUP BY is employed to group rows sharing common values in specified columns, enabling aggregation functions to summarize data within each group. The following SQL statement selects only the DISTINCT values from the "Country" column in the "Customers" table: The DISTINCT keyword is an important tool in SQL to retrieve unique rows from a table or join result set. Apr 23, 2021 · The DISTINCT keyword in SQL plays an important role in removing duplicate values from your results. The DISTINCT keyword Oct 10, 2024 · SQL Query Types and Introduction to the MySQL DISTINCT Clause SQL queries have a couple of distinct types, and they all perform different tasks: some insert data, some update, and some delete it. This important feture can be used as SQL distinct statement, sql distict count, sql join distinct, SQL count distinct multiple column, SQL distinct group by, SQL sum distinct Jun 19, 2016 · DISTINCT (or DISTINCTROW) is not a function; it is an option of the SELECT statement that tells MySQL to strip duplicate rows from the resultset generated by the query. Jul 23, 2025 · The DISTINCT clause is used in a SELECT statement to remove duplicate rows from the result set. Feb 7, 2025 · SQL COUNT() with DISTINCT: SQL COUNT() function with DISTINCT clause eliminates the repetitive appearance of a same data. Jan 19, 2024 · In this tutorial, you will learn how to use the MySQL DISTINCT clause in the SELECT statement to eliminate duplicate rows in a result set. The DISTINCT clause can only be used with SELECT statements. 1 简单的用法1. g. The DISTINCT clause is used for retrieving unique values from a column or combination of columns in MySQL. To do this, you need to use an aggregate function to sort on, and use a GROUP BY to make the DISTINCT work. Oct 8, 2021 · The MySQL DISTINCT clause (or keyword) is used to remove duplicate values from the result set of your query, making sure that all rows in the result set are unique records. Jul 21, 2025 · Learn how to count distinct values in SQL with COUNT DISTINCT function. Oct 2, 2020 · MySQL DISTINCT helps you find out the distinct or unique values from a table. This is very helpful as it omits the duplicate values from the result-set and returns only the distinct values. This tutorial shows you how to use the SQL DISTINCT operator to select distinct rows from a result set in the SELECT statement. Learn how to use it in different scenarios and what its alternatives are. 8, “INTERSECT Clause”, is shown here: I need to query an SQL database to find all distinct values of one column and I need an arbitrary value from another column. May 29, 2016 · Are you talking about mysql or sql-server? In either case, distinct probably works as designed and your assumptions are just not correct. If you’re not familiar already, SELECT DISTINCT is a handy tool in our SQL arsenal that helps to return unique values within a database column. How can I use the DISTINCT clause with WHERE? For example: SELECT * FROM table WHERE DISTINCT email; -- email is a column name I want to select all columns from a table with distinct email addresses. Check examples showing exactly how DISTINCT works. Jan 11, 2024 · In this comprehensive guide, you will learn more about distinct in SQL server. MySQL supports UNION, INTERSECT, and EXCEPT. This tutorial is a part of several posts explaining how to write basic queries in MySQL. The DISTINCT operator may be used only with SELECT operators. Jul 23, 2025 · The SELECT DISTINCT statement in SQL is an essential tool for retrieving unique combinations of values from multiple columns. The SQL DISTINCT clause is a handy tool for removing duplicate rows from your query results, ensuring you get only unique values. comYou completed the SQL Select Distinct Exercises from W3Schools. Jan 21, 2024 · SQL SELECT DISTINCT is a powerful statement for removing duplicates from your data. So, basically, it means that every row returned in the result will be unique in terms of the combination of the select query columns. For example, consider the following table with two columns, key and val DISTINCT keyword is supposed to be applied to all the columns in the select query and not just to the column next to which DISTINCT keyword is written. Any ideas? (Using php/mysql) MAJOR EDIT: Forgot an important piece of information. Jun 16, 2009 · Use a distinct with a subquery which contains a union select distinct product_type from ( select product_type from table 1 union select product_type from table 2 ) t The "t" at the end is the alias to the subquery, so, you can say t. SELECT DISTINCT MIN(t. 2 distinct 的注意事项02 可能遇到的其他用法2. In this tutorial, you will learn about the SQL DISTINCT clause with the help of examples. I'm trying to get unique dates based on month and year. The SELECT DISTINCT statement in MySQL is used to retrieve unique values from a specified column or combination of columns in a table. Sample Data The examples on this page use the following data: SELECT This SQL Server tutorial explains how to use the DISTINCT clause in SQL Server (Transact-SQL) with syntax and examples. This guide provides syntax explanations, practical examples, and best practices for efficient data querying. the last set of records with distinct codes (based on datetime value). produc_type and it'll mean "the field product_type from the subquery called t". The SQL DISTINCT clause is used to remove duplicates from the result set of a SELECT statement. 2 计数 count (distinct c)总结REFERENCESMySQL distinct 去重在使用 MySQL 时，有时需要… SELECT DISTINCT The SELECT DISTINCT command returns only distinct (different) values in the result set. Jun 12, 2024 · 在数据库操作中，去重是一个比较常见的需求。MySQL 提供了多种方法来实现数据去重，包括使用 DISTINCT 关键字、窗口函数和 GROUP BY 等方法。本小节中，就将详细介绍一下这些方法，帮助你在不同场景下实现数据去重。 Jul 11, 2024 · MySQL GROUP_CONCAT() function returns a string with concatenated non-NULL value from a group. Here we show, How to write Distinct rows. The DISTINCT keyword is used in a select statement before the target column name. Oct 21, 2023 · The DISTINCT keyword is typically used in the SELECT list of a query, but some RDBMSs allow for it to be placed in other parts of the query, such as the GROUP BY clause and the WINDOW clause. This tutorial shows you how to use the Oracle SELECT DISTINCT operator to get distinct rows based on one or more columns. Learn how to use the MySQL DISTINCT keyword to filter out duplicate entries and retrieve unique values in your database queries efficiently. Feb 19, 2017 · Then at the end you put the distinct column to filter and you only group it with that last distinct column. In practice, this command looks like this: SELECT DISTINCT column_name FROM table_name You can Aug 11, 2025 · The DISTINCT keyword in SQL is used to retrieve only unique values, eliminating duplicates from query results. GROUP_CONCAT(expr) This function returns a string result with the concatenated non- NULL values from a group. When applied, it ensures that only unique records are returned, eliminating any redundant data. Learn how to use MySQL's `DISTINCT` keyword to filter unique records and simulate `DISTINCT ON` functionality with subqueries and window functions for efficient data retrieval. May 17, 2023 · Guide to MySQL DISTINCT. Thus, for more details on the optimization possibilities for DISTINCT queries, see Section 8. DISTINCT only but GROUP BY seems to them in addition. DISTINCT will eliminate those rows where all the selected fields are identical. Once it is persisted, provided the column is deterministic and you are using "sane" database settings, it can be indexed and / or statistics can be created on it. token, t. 17, “GROUP BY Optimization”. Sep 12, 2021 · 1 MySQL 5. 7, several user-visible effects resulted from this work, which may require rewriting of certain statements: Dec 27, 2024 · When to Use DISTINCT in SQL We just saw a simple demonstration, but in real-world queries you will often be selecting data from multiple tables that can produce duplicates. In this comprehensive guide, you’ll learn how to use DISTINCT to eliminate duplicate rows in SQL queries. This example uses SELECT statements: MySQL DISTINCT statement is used to remove duplicates from the result set. 6 approach If you're still looking for a way to use the DISTINCT statement, you can do this using the GROUP BY approach below. The SQL DISTINCT command used along with the SELECT keyword retrieves only unique data entries depending on the column list you have specified after it. For SQL_BIG_RESULT, MySQL directly uses disk-based temporary tables if they are created, and prefers sorting to using a temporary table with a key on the GROUP BY elements. An example using the tables a, b, and c defined in Section 15. id) AS id, t. We use DISTINCT keyword with the SELECT statetment when there is a need to avoid duplicate values present in any specific columns/tables. SQL Distinct Tutorial with Examples The DISTINCT SQL command is used in conjunction with the SELECT statement to return only distinct (different) values. The DISTINCT clause operates on the values of the expressions present in the SELECT clause. The DISTINCT clause in MySQL is used with a SELECT statement to return the distinct values (unique values) from a single or multiple of columns in a table. Nov 27, 2023 · The SQL DISTINCT query is used to eliminate duplicates. When you use the SELECT SQL query, you can choose one or more columns from a table. If you do not use columns from all Learn how to use the MySQL COUNT DISTINCT function to count the number of unique values in a specific column of a table. I tried SELECT DISTINCT TOP 10 * FROM TableA but I still have a duplicate personID, so I tought to do: SELECT DISTINCT (personID) TOP 10 * FROM Ta Feb 14, 2017 · 0 In MySQL, DISTINCT seems a bit faster than GROUP BY if theField is not indexed. text FROM `chatMessages` AS t GROUP BY `token` DESC Trying with the sample data below CREATE TABLE IF NOT EXISTS `chatMessages` ( If you use another browser you will still be able to use our Try SQL Editor, but a different version, using a server-based ASP application, with a read-only Access Database, where users are not allowed to make any changes to the data. If row #1 is processed first then (A, B) is placed in the result set and it is associated with row #1. Dec 27, 2012 · 0 If you are using an SQL dialect which supports FILTER on counts, such as Postgresql, you can write ntalbs's answer in the slightly more readable form SELECT COUNT(DISTINCT tag) AS tag_count, COUNT(DISTINCT tag) FILTER (WHERE entryID > 0) AS positive_tag_count FROM your_table_name; This generalizes to all aggregate functions. 21 for osx10. May 25, 2011 · SELECT DISTINCT FIELD1, FIELD2, FIELD3 FROM TABLE1 works if the values of all three columns are unique in the table. It simplifies data queries, removes redundancy, and makes the results cleaner and more meaningful. Aug 26, 2025 · Master the SQL DISTINCT clause with clear syntax, examples, COUNT DISTINCT usage, and practical tips for fetching unique values in SQL tables. This chapter covered how to use the DISTINCT clause, including examples of retrieving unique values, combining it with other clauses like WHERE, ORDER BY, and LIMIT. Jul 23, 2025 · We can use the DISTINCT keyword and GROUP BY clause when we want to obtain the unique records of a table in SQL. All three set operators also support a DISTINCT keyword, which suppresses duplicates in the result Feb 23, 2020 · The DISTINCT operator in SQL allows coders to eliminate duplicate values and return unique results from a table. SELECT DISTINCT (SQL SELECT DISTINCT Statement) 一個資料表的某欄位中可能會有多個紀錄都是相同值的情況，在 SELECT 查詢語句中我們可使用 DISTINCT 關鍵字過濾重複出現的紀錄值。 Feb 8, 2024 · In MySQL, SELECT DISTINCT is used to retrieve unique values from one or more columns in a result set, eliminating duplicates without aggregation. In this tutorial, we explain everything you need to know. EmailAddress). Jul 31, 2024 · DISTINCT on multiple columns In SQL multiple fields may also be added with DISTINCT clause. This MySQL tutorial explains how to use the MySQL DISTINCT clause with syntax and examples. user_id=12, TRUE, FALSE) as is_enrolled from `courses` inner join ` If you do not want to see entire rows from your table, just name the columns in which you are interested, separated by commas. This method is often used for reporting categories, users, or identifiers in a database without duplicates. Jul 31, 2025 · Using DISTINCT and COUNT together in SQL is a common technique to count the number of unique values in one or more columns. SQL_BIG_RESULT or SQL_SMALL_RESULT can be used with GROUP BY or DISTINCT to tell the optimizer that the result set has many rows or is small, respectively. When retrieving data from a database, it’s common to encounter multiple identical entries across selected columns. 7 In MySQL 8. This article will explore how to use the DISTINCT keyword in MySQL to effectively return unique data in your SQL pulls. Sep 6, 2021 · In this post, we'll find out what impact have SELECT DISTINCT and GROUP BY on database performance by analyzing their query execution plans. e. Use DISTINCT to remove duplicate rows from the results of an SQL statement. I completed a SQL exercise on w3schools. See examples, equivalences, and optimization possibilities for DISTINCT queries. drugClass) OVER(PARTITION BY rx. This SQL tutorial focuses on the MySQL DISTINCT keyword, and provides explanations, examples and exercises. Jul 23, 2025 · Count Distinct Values from Multiple Columns in MySQL To perform operations related to counting distinct values in MySQL, we need to create a table in our database first. patid, rx. SELECT DISTINCT The SELECT DISTINCT command returns only distinct (different) values in the result set. In this tutorial, we’ll learn how to SUM DISTINCT rows in SQL. Learn how MySQL handles DISTINCT clauses with ORDER BY, GROUP BY, and LIMIT in different cases. I believe a distinct count of the computed column would be equivalent to your query. Real-world […] The SQL DISTINCT Keyword The SQL DISTINCT keyword is used in conjunction with the SELECT statement to fetch unique records from a table. Aug 8, 2013 · I am fighting with the distinct keyword in sql. Each of these set operators supports an ALL modifier. Learn how to use the SQL SELECT DISTINCT statement to return only distinct values from a table. To illustrate the usage of the DISTINCT keyword, we'll use our Users table introduced in the previous chapters. 15 on x86_64 (Homebrew) DISTINCT とは 指定したカラムにおいて重複するデータを取り除いて出力することができる機能。 SQL_BIG_RESULT or SQL_SMALL_RESULT can be used with GROUP BY or DISTINCT to tell the optimizer that the result set has many rows or is small, respectively. Apr 5, 2021 · In this article we look at how to retrieve a list of distinct datasets from SQL Server without repeating information using the DISTINCT clause. qitd emiig hzxmpb fpcpo caql yqpvxzej wpo jcmq xrqnje jan