参考官方文档https://support.microsoft.com/zh-cn/help/139444/how-to-remove-duplicate-rows-from-a-table-in-sql-serverlink 原文摘录 需要检查是否是除了id列之外的整行重复,请对比所有列之后,选择需要保留的行 只有几组重复的 PK 值(手动删除) 在该示例中,我们将使用下表,它具有重复的 PK 值。 在该表...
SELECTDISTINCT*INTOduplicate_tableFROMoriginal_tableGROUPBYkey_valueHAVINGCOUNT(key_value) >1DELETEoriginal_tableWHEREkey_valueIN(SELECTkey_valueFROMduplicate_table)INSERToriginal_tableSELECT*FROMduplicate_tableDROPTABLEduplicate_table 此脚本按给定顺序执行以下操作: ...
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...
If you execute the DELETE table command without the WHERE condition, you will end up deleting all the rows (data) from the table. Hence, make it a habit to use the WHERE condition unless you want to remove all rows. Compatibility This statement is compatible with many versions of SQL Serv...
ROW_NUMBER WF enumerates the rows. We can also use it to remove duplicate records with it. Or to take a random sample. As the name suggests WF can calculate statistics on a given window: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 ...
FROM mytable WHEREcondition(s)ORDERBY column ASC/DESC LIMIT num_limit OFFSET num_offset; 查询结果: 1.selectdistinct director from movies order by director asc; where语句可以不写,灵活使用 Since theDISTINCTkeyword will blindly remove duplicate rows, ...
EXPLAINSELECT*fromt_table_1wheretask_idin(selectidfromt_table_2whereuid=1) explain后可以看到是走了索引的 到这里可以总结: 1.没有死锁,这点比较肯定,因为没有日志,也符合我们的理解。 2.有慢sql,这点比较奇怪,通过explain select语句是走索引的,但数据库慢日志记录到,全表扫描,不会错。
SELECT class_num, class_name FROM class WHERE class_num IN (SELECT class_num FROM roster); semijoin有以下几种策略,以下是官方的解释:Duplicate Weedout: Run the semijoin as if it was a join and remove duplicate records using a temporary table. FirstMatch: When scanning the inner tables for...
Add rows to a Table in run time , one by one Add Trusted Site in the IIS server Adding .ASHX files to an existing Project... Adding a asp:button in Literal control. Adding a hyperlink text in the email message body in outlook from asp.net Adding a link within a label.text value...
You can then remove the offending rows using uncorrelated deletes (if the driving column is unique across the whole table) or correlated deletes (if it's only unique within each duplicate group). Whichever approach you take, it's a good idea to create an unvalidated unique constraint first....