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: ...
在SQL Server 中,去重通常可以通过使用DISTINCT关键字、GROUP BY子句或者ROW_NUMBER()函数来实现。我们接下来将详细说明这些方法。 2. 使用DISTINCT DISTINCT关键字用于从结果集中返回不同的值。它通常用于单列或多列的查询中,以消除重复结果。 示例代码: SELECTDISTINCTcolumn1,column2FROMyour_table; 1. 2. 上面的...
Now we have realized that custid 1, 4 & 5 are duplicate. The self-join statement accompanied by delete statement will give us the desired output of keeping the last duplicate record by eliminating all the previous duplicate records. We will use theCommon Table Expression (CTE)and put the Sel...
CREATE TABLE TestBatch (ColA INT PRIMARY KEY, ColB CHAR(3)); GO INSERT INTO TestBatch VALUES (1, 'aaa'); INSERT INTO TestBatch VALUES (2, 'bbb'); INSERT INTO TestBatch VALUES (1, 'ccc'); -- Duplicate key error. GO SELECT * FROM TestBatch; -- Returns rows 1 and 2...
(0 rows affected) Raise the caught error again Msg 2627, Level 14, State 1, Line 10 Violation of PRIMARY KEY constraint 'PK__t1__3213E83F906A55AA'. Cannot insert duplicate key in object 'dbo.t1'. The duplicate key value is (1). 在这个示例中,第一条INSERT语句成功了。但是,由于主键约...
为了能够创建序列对象,需要CREATE SEQUENCE权限。 SQL Server 2012中还引入了CREATE SEQUENCE权限。有关此新权限的详细信息,请运行以下脚本: AI检测代码解析 select * from sys.fn_builtin_permissions (DEFAULT) ORDER BY class_desc, permission_name;
CREATE TABLE TestBatch (ColA INT PRIMARY KEY, ColB CHAR(3)); GO INSERT INTO TestBatch VALUES (1, 'aaa'); INSERT INTO TestBatch VALUES (2, 'bbb'); INSERT INTO TestBatch VALUES (1, 'ccc'); -- Duplicate key error. GO SELECT * FROM TestBatch; -- Returns rows 1 and 2. GO 数...
SQL Server selects specific rows to compress according to their last update time. For example, if rows are changing frequently during a two-hour period of time, you could set COMPRESSION_DELAY = 120 Minutes to ensure updates are completed before SQL Server compresses the row. For a disk-...
Using: TSQL / SQL Server 2008 Goals: Don't include "duplicate" rows What are duplicates in this context? Two scenarios: For some tables, if two rows have the same value in all columns. ex "*" For other tables, if two rows have the same value in some columns ex. "COL_A, CO...
Applies to: SQL Server 2008 (10.0.x) SP 1 and later versions. Specifies the assembly and method to which the created function name shall refer. assembly_name - must match a value in the name column of SELECT * FROM sys.assemblies;. The name that was used on the CREATE ASSEMBLY statemen...