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...
Let’s check which rows got deleted. select * from customers2 go Scenario 2.b: Delete all duplicate records but keep the first original one Let’s first truncate the customers2 table and add the same rows again. Truncate Table customers2 go Insert into customers2 Values(1, 'John', 'Pari...
WF can perform an additional aggregation on already aggregated data with GROUP BY. See the example in the image above, where I calculate sales all with a WF. 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...
proctimeASPROCTIME() )WITH(...);--remove duplicate rows on order_id and keep the first occurrence row,--because there shouldn't be two orders with the same order_id.SELECTorder_id,user, product, numFROM(SELECT*, ROW_NUMBER()OVER(PARTITIONBYorder_idORDERBYproctimeASC)ASrow_numFROMOrders)...
然後,請嘗試下列方法,從資料表中移除重複列。 方法1 執行下列指令碼: SQL 複製 SELECT DISTINCT * INTO duplicate_table FROM original_table GROUP BY key_value HAVING COUNT(key_value) > 1 DELETE original_table WHERE key_value IN (SELECT key_value FROM duplicate_table) INSERT origi...
FirstMatch:Whenscanning the inner tablesforrow combinationsandthere are multiple instancesofa given valuegroup, choose one rather than returning them all. This"shortcuts"scanningandeliminates productionofunnecessary rows. LooseScan:Scan a subquery tableusingan index that enables asinglevaluetobe chosenfromea...
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, I'm going to assume that either the rows are exact copies or you don't care which you remove. ...
This "shortcuts" scanning and eliminates production of unnecessary rows. LooseScan: Scan a subquery table using an index that enables a single value to be chosen from each subquery's value group. Materialize the subquery into an indexed temporary table that is used to perform a join, where ...
How to delete duplicate records from datatable How to Delete row with link button in repeater How to delete rows from a Gridview ==c# web form asp.net How to delete(logout) Form Authentication cookies in MVC5? How to Deserialize a Json JArray how to detect browser close event in jquery...
The following examples useUNIONto combine the results of three tables that all have the same five rows of data. The first example usesUNION ALLto show the duplicated records, and returns all 15 rows. The second example usesUNIONwithoutALLto eliminate the duplicate rows from the combined results...