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 a list to thedropDuplicates()method. After execution, thedropDuplicates()method will return a dataframe containing a unique set of values in the specified...
[ 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> ] [...
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...
The DISTINCT clause is used in a SELECT statement to filter duplicate rows in the result set. It ensures that rows returned are unique for the column or columns specified in the SELECT clause. The following illustrates the syntax of the SELECT DISTINCT statement: SELECT DISTINCT column_1 FROM ...
SELECT DISTINCT的基本语法如下: 代码语言:sql 复制 SELECTDISTINCTcolumn1,column2,...FROMtable_name; 其中,column1,column2,等是您要选择不同值的列名称,而table_name是您从中选择不同值的表的名称。 以下是一些示例: 从"Customers"表中选择不同的国家: ...
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....
Select distinct combinations of 'agent_code' and 'ord_amount'FROMorders-- From the table 'orders'WHEREagent_code='A002'-- Filter the results to only include rows where the 'agent_code' is 'A002'ORDERBYord_amount;-- Sort the results in ascending order based on the 'ord_amount' column ...
SELECT DISTINCT accountid FROM table; COUNT DISTINCT子句 命令简介 COUNT DISTINCT支持计算去重之后的某一个column的个数,对于该列中出现多次的值只会被计算一次,和COUNT的计算类似,如果该列包含NULL值,它将不会计算在内。 语法说明 精确计算的语法示例如下: SELECT c1, COUNT(DISTINCT c2) FROM table GROUP BY...
SELECT DISTINCT on one column, with multiple columns returned Select event where date >= today SELECT INTO temporary table with unique key? SELECT not DISTINCT records in Table Select with from database with a list of parameters Selecting columns from a datatable for a dataview.. Selecting N...
The problem is that the "DISTINCT" query takes AGES to complete. I don't actually know how long, because I stopped the query after 25 minutes. Is there a faster way for me to get unique values from a column? Subject Written By