2020 年 8 月 12 日,由 Robert Gravelle 撰寫將DISTINCT 關鍵字加入 SELECT 查詢後,查詢僅傳回指定欄清單的唯一值,以便從結果集中移除重複的列。由於 DISTINCT 會在 SELECT 的欄清單中的所有欄位運作,因此不能將其用於一組欄位中的其中一個欄位。話雖如此,但是也有多種方法可以無視其他欄並從一欄中移除重複...
SELECT DISTINCT column_1 FROM table;Code language: SQL (Structured Query Language) (sql) In this statement, the values in the column_1 of the table are compared to determine the duplicates. To retrieve unique data based on multiple columns, you just need to specify the column list in the ...
SELECT column aliases: Refer to alias in another column? SELECT COUNT from 2 intersected tables select count(*) Select DISTINCT in LEFT JOIN SELECT DISTINCT on one column, with multiple columns returned Select event where date >= today SELECT INTO temporary table with unique key? SELECT not ...
Count Detail Records based on a condition in SSRS Count Occurrences of a Specific Value in a Delimited String or Array Count rows in a filtered tablix Count the number of rows in a row group within a matrix with both row groups and column groups CountDistinct with condition? CountIf Expressi...
DISTINCT 指定在结果集中只能包含唯一行。 对于 DISTINCT 关键字来说,Null 值是相等的。 TOP (expression ) [ PERCENT ] [ WITH TIES ] 指示只能从查询结果集返回指定的第一组行或指定的百分比数目的行。expression可以是行数或行的百分比。 为了能够向后兼容,支持在 SELECT 语句中使用不带括号的 TOP expression...
[WITH<common_table_expression>[ , ...n ] ]SELECT<select_criteria>[ ; ]<select_criteria>::=[TOP(top_expression) ] [ALL|DISTINCT] { * |column_name| expression } [ , ...n ] [FROM{table_source} [ , ...n ] ] [WHERE<search_condition>] [GROUPBY<group_by_clause>] [HAVING<search...
June 15, 2009 03:39PM Re: SELECT DISTINCT on certain column? Guelphdad Lake June 15, 2009 08:24PM Re: SELECT DISTINCT on certain column? Dave Kennard June 16, 2009 03:48AM Sorry, you can't reply to this topic. It has been closed....
SQL的SELECT DISTINCT语句用于选择表中的不同(唯一)值。这在某些情况下非常有用,因为数据库表中的某些列可能包含大量重复值,而您只关心获取这些值的不同实例。 SELECT DISTINCT的基本语法如下: 代码语言:sql 复制 SELECTDISTINCTcolumn1,column2,...FROMtable_name; ...
In the previous examples, we have selected unique rows based on all the columns. However, we can also use specific columns to decide on unique rows. To select distinct rows based on multiple columns, we can pass the column names by which we want to decide the uniqueness of the rows in ...
Since DISTINCT operates on all of the fields in SELECT's column list, it can't be applied to an individual field that are part of a larger group. That being said, there are ways to remove duplicate values from one column, while ignoring other columns. We'll be taking a look at a ...