length(str) : 返回给定字符串的长度,如 length("string")=6 substr(string,start,length):对于给定字符串string,从start位开始截取,截取length长度 ,如 substr("chinese",3,2)="in" substr()、stbstring()、mid() :三个函数的用法、功能均一致 concat(username):将查询到的username连在一起,默认用逗号分隔...
Applies to: SQL Server Is the logical name of the backup device to which the database is backed up. The logical name must follow the rules for identifiers. If supplied as a variable (@logical_device_name_var), the backup device name can be specified either as a string constant (@logical...
The name of a column in the table. Column names must comply with the rules for identifiers and must be unique in the table. column_name can consist of 1 through 128 characters. data_type Specifies the column data type. For Transact-SQL functions, all data types, including CLR user-defined...
@source_string)set@count=0while@postion>0beginset@count=@count+1if@count=@nthbeginbreakendset@postion=CHARINDEX(@sub_string,@source_string,@postion+1)Endreturn@postionendGO--select dbo.NthChar('abcabc','abc',2)--4
The name of a column in the table. Column names must comply with the rules for identifiers and must be unique in the table. column_name can consist of 1 through 128 characters. data_type Specifies the column data type. For Transact-SQL functions, all data types, including CLR user-defined...
PRINT '*** Setting ANSI_WARNINGS OFF'; GO SET ANSI_WARNINGS OFF; GO PRINT 'Testing NULL in aggregate'; GO SELECT a, SUM(b) FROM T1 GROUP BY a; GO PRINT 'Testing String Overflow in INSERT'; GO INSERT INTO T1 VALUES (4, 4, 'Text string longer than 20 characters'); GO SELECT a...
适用于 SQL Server 的 Microsoft OLE DB 驱动程序 对于作为 SQL Server 数据库引擎组件(版本 2012 到 2019)随附的 SQLNCLI,请参阅此支持生命周期特例。 在SQL Server 2005 (9.x) 之前,若要使用大值数据类型,必须进行特殊的处理。 大值数据类型是超过最大行大小 8 KB 的数据类型。 SQL Server 2005 (9.x...
PRINT '*** Setting ANSI_WARNINGS OFF'; GOSETANSI_WARNINGSOFF; GO PRINT 'Testing NULL in aggregate'; GOSELECTa,SUM(b)FROMT1GROUPBYa; GO PRINT 'Testing String Overflow inINSERT'; GO INSERT INTO T1 VALUES (4, 4, 'Textstringlongerthan20characters'); GO SELECT a, b, c FROM T1 WHERE a...
Array data type in SQL server Array's IN SQL SERVER? ASCII values for extended characters Assign empty string '' if datetime is null Assign EXEC output to Variable Assigning NULL value to column name using Case Statement of where is SQL SERVER 2008 atomic if not exists() and insert or upd...
trim([characters from] string):去掉字符串头尾指定的空格或字符。 regexp_extract(string, pattern, index):指定模式,并返回特定位置(从1开始计算)的匹配结果。 regexp_replace(string, pattern, replacement):将字符串中的符合模式的字符串替换成替换字符串。