,可以使用DISTINCT关键字来实现。DISTINCT关键字用于返回唯一不重复的结果集。 在SQL中,可以使用SELECT语句来查询数据。如果查询结果中存在几乎重复的行,可以通过在SELECT语句...
Except、Intersect、Union三种set符号是默认进行unique处理,当进行unique处理时会进行如下两步操作 1. PROC SQL eliminates duplicate (nonunique) rows in the tables. 2. PROC SQL selects the rows that meet the criteria and, where requested, overlays columns. 当进行的操作同时需要展现unique和duplicate行时则...
Select * into #Temp_customers1 from customers1 where 1 = 2 Insert into #Temp_customers1 select * from customers1 Group by Custid,CustName, CustCity, Passport_Number Having count(*) > 1 Now the situation is that the duplicate row is in the local temporary table. All we need to now is...
TheSELECT DISTINCTstatement is used when you want to return only unique (distinct) values in the result set. Whereas, a regularSELECTstatement without theDISTINCTkeyword retrieves all rows from the specified columns, including duplicate values. Let's look at an example. Example: SELECT DISTINCT -...
SELECT DISTINCT agent_code, ord_amount, cust_code, ord_num: This line specifies that you want to retrieve unique combinations of 'agent_code', 'ord_amount', 'cust_code', and 'ord_num'. The DISTINCT keyword ensures that only unique combinations are returned; any duplicate combinations will ...
ERROR 1062 (23000): Duplicate entry 'value' for key 'PRIMARY' 1. 解决方案: sql 复制下载 -- 使用INSERT IGNORE跳过重复记录 INSERT IGNORE INTO table_name VALUES (...); -- 使用ON DUPLICATE KEY UPDATE更新重复记录 INSERT INTO table_name VALUES (...) ...
开始我们拿sql到数据库查询平台查库执行计划,无奈这个平台有bug,delete语句无法查看,所以我们改成select,“应该”是一样。这个“应该”加了双引号,导致我们走了一点弯路。 EXPLAINSELECT*fromt_table_1wheretask_idin(selectidfromt_table_2whereuid=1)
SELECT*FROMtbl_nameWHEREprimary_key=1;SELECT*FROMtbl_nameWHEREprimary_key_part1=1ANDprimary_key_part2=2; eq_ref 对于前面表的每个行组合,从这个表中读取一行。除了system和const类型之外,这是最好的可能的连接类型。当索引的所有部分都被连接使用,并且索引是PRIMARY KEY或UNIQUE NOT NULL索引时,会使用eq_...
select * from film_counts where ct > 1 With a list of the duplicates in hand, it's time for the next step! How to Delete the Duplicate Rows Delete key1by Büşra ÖZCOŞKUNCC BY-SA 4.0 Now you've identified the copies, you often want to delete the extra rows. For simplicity,...
(stmt=select a.num1,decode(a.num2,0,decode(a.num3,(-1),2,0),a.num2) cc from test a group by num1 ,decode(a.num2,0,decode(a.num3,(-1),2,0),a.num2) order by decode(a.num2,0,decode(a.num3,(-1),2,0),a.num2), ret=-5218) observer.log.20241228204741911:[2024-...