Article Introduction：SQL DISTINCT 关键字通过比较所有列值来去除重复行，只保留唯一的行。用法包括以下步骤：指定要选择的列名，后跟 DISTINCT 关键字。指定要查询的表名。DISTINCT 可以应用于一个或多个列。与 GROUP BY 不同，DISTINCT 直接去除重复行而不进行分组。

2024-06-12comment 0944

Article Introduction：distinct() command: distinct function: deduplication application scenario: when statistical type, status, and distinction are required. Example: mysql>selectcount(distinct(name))/count(*)fromt_base_user;+---------------------------------- -+|count(distinct(name))/count(*)|+--------------------------------+ |0.6667|+--------------------------------

2023-05-27comment 0611

Article Introduction：In mysql, the distinct keyword is used to filter duplicate data. It can filter duplicate data in one or more fields in the data table and only return one piece of data to the user; the distinct keyword needs to be used together with the SELECT statement. The syntax "SELECT DISTINCT column1, column2, ... FROM table_name;".

2022-11-08comment 011298

Article Introduction：The DISTINCT keyword is used to remove duplicate rows from MySQL query results, leaving only unique values. Its usage includes: DISTINCT column_name: Remove duplicate values from the specified column. DISTINCT(column_name1, column_name2, ...): Remove duplicate values from a combination of multiple columns.

2024-04-26comment 0782

Article Introduction：The DISTINCT keyword in SQL is used to remove duplicate rows from query results. It can be applied to one or more columns in the SELECT statement to return a unique value combination. The usage method is "SELECT DISTINCT column1, column2, ..." The DISTINCT keyword acts on all specified columns. If multiple columns are combined to produce different results, then these rows will also be considered different and will not be deduplicated.

2024-01-25comment 0758

Article Introduction：DISTINCT in SQL is a keyword used to query unique result sets. It can be used in SELECT statements, COUNT aggregate functions and other statements. The basic syntax is "SELECT DISTINCT column1, column2", where the DISTINCT keyword is placed in the SELECT key After the word, followed by the column name or expression to be queried, separated by commas.

2024-01-26comment 0124

Article Introduction：DISTINCT 在 SQL 中用于去除查询结果中的重复行，仅返回唯一值。其工作原理是在特定列或表达式上进行比较，如果某行中的值与之前的任何一行都不同，则该行将包含在结果集中；否则，该行将被丢弃。语法：SELECT DISTINCT column_name(s) FROM table_name; 例如，使用 DISTINCT 查询不重复的名称：SELECT DISTINCT name FROM table_name; 注意：DISTINCT 仅用于 SELECT 语句，只能对一列或表达式求值，可能降低查询性能。

2024-05-15comment477

Article Introduction：The syntax of distinct in SQL is "SELECT DISTINCT column1, column2,...,FROM table_name;", where column1, column2, etc. represent the column names to be queried, and table_name represents the table name to be queried. When using the DISTINCT keyword, SQL will remove duplicate rows based on the specified columns and return unique values.

2023-10-27comment 0332

Article Introduction：In thinkphp, the distinct() method is used to remove duplicate values and can return unique values. The parameter of the distinct method is a Boolean value, and the syntax is "$Model->distinct (Boolean parameter)->field('name ')->select();".

2022-04-24comment 05372

Article Introduction：DISTINCT is an operator in MySQL used to remove duplicate rows from a result set. It retains unique values within the same column or set of columns. Usage: 1. Used with the SELECT statement to select unique values from a table. 2. Syntax: SELECT DISTINCT column_name(s) FROM table_name. 3. For example: SELECT DISTINCT name FROM customers;

2024-04-27comment 0159

Article Introduction：SQL 中使用 DISTINCT 去重有两种方法：SELECT DISTINCT：仅保留指定列的唯一值，保持原始表顺序。GROUP BY：保留分组键的唯一值，重新排序表中行。

2024-06-12comment 0592

Article Introduction：Oracle's distinct usage can filter duplicate rows in the result set to ensure that the value of the specified column or columns returned in the "SELECT" clause is unique. The syntax is "SELECT DISTINCT column 1, column 2, column 3... from table name". "distinct" will sort the returned result set and can be used in conjunction with "order by" to improve efficiency.

2023-07-11comment 03005

Article Introduction：Oracle's distinct usage can filter duplicate rows in the result set to ensure that the value of the specified column or columns returned in the "SELECT" clause is unique. The syntax is "SELECT DISTINCT column 1, column 2, column 3... from table name". "distinct" will sort the returned result set and can be used in conjunction with "order by" to improve efficiency.

2023-09-05comment 0465

Article Introduction：The DISTINCT operator removes duplicate rows from a result set and can be used to extract unique values or eliminate duplicate rows in join results. It can be applied to a single table, use multiple tables to eliminate duplicate rows, or use multiple columns as parameters. DISTINCT may affect query performance because it does not utilize indexes and may increase processing time.

2024-05-02comment 0306

Article Introduction：[mysql distinct] filters duplicate data in one or more fields in the database table and returns only one piece of data to the user. Its usage is: [select distinct field name from table name] to return unique field names.

2020-06-13comment 04096

Article Introduction：distinct() 方法去除流中重复元素，返回一个仅包含不重复元素的新流。语法：Stream distinct()。用法：使用自定义比较器可按属性比较元素；流管道可先过滤元素再去除重复。实现基于 HashMap，时间复杂度为 O(n)。

2024-05-12comment 0463

Article Introduction：Detailed explanation of distinct usage in SQL In SQL databases, we often encounter situations where we need to remove duplicate data. At this time, we can use the distinct keyword, which can help us remove duplicate data and make the query results clearer and more accurate. The basic usage of distinct is very simple, just use the distinct keyword in the select statement. For example, the following is a normal select statement: SELECTcolumn_name

2024-02-18comment 0992

Article Introduction：In laravel, the distinct() method is used to force the search to return unique results. The syntax is "$users=DB::table('users')->distinct()->get();"; if you use To find multiple fields, specify the select field and add the field names.

2022-06-06comment 02390

Article Introduction：SQL 中的 DISTINCT 关键字用于从查询结果中删除重复的行。 它保留每个表的唯一行，丢弃重复值。使用时，在 SELECT 语句开头紧跟在结果列后面，例如：SELECT DISTINCT 列名1, 列名2 FROM 表名; DISTINCT 的好处包括消除重复值，简化数据分析，提高查询性能，确保结果唯一性。但它仅删除重复行，不影响行内字段排序，并且可能导致查询性能下降。

2024-06-25comment385

Article Introduction：DISTINCT 操作符用于 SQL 查询中排除重复行，仅返回唯一值，适用于获取唯一值列表、统计唯一值数量和结合 GROUP BY 使用等场景。

2024-06-03comment583