datediff function in sql

,datalengthO:length www.knowsky.com28. Capitalization Conversion Lower,upper 29. Capitalize the first letter of the wordS: I didn't find it.O:select initcap (' ABCD Dsaf df ') value from dual 30. Left fill space (the first parameter of Lpad is a space function)S:select space + ' ABCD ' valueO:select lpad (' ABCD ') value from dual 31. Right complement space (the first parameter of Rpad is a space function)S

SQL Date Data typeSQL Server uses the following data types to store date or date/time values in the database: DATE-Format YYYY-MM-DD DATETIME-format: Yyyy-mm-dd HH:MM:SS smalldatetime-format: Yyyy-mm-dd HH:MM:SS TIMESTAMP-Format: Unique number Use the following SELECT statement:SELECT GETDATE () as CurrentdatetimeThe DATEPART () function is used to return a separate part of a date/

:00. 000SQL DATENAME ()DATENAME (day, '2017-09-30 11:35:00. 100') = 30DATENAME (month, '2017-09-30 11:35:00. 100') = SeptemberDATENAME (year, '2017-09-30 11:35:00. 100') = 2008DATENAME (hour, '2017-09-30 11:35:00. 100') = 11DATENAME (minute, '2017-09-30 11:35:00. 123') = 35DATENAME (second, '2017-09-30 11:35:00. 100') = 0DATENAME (quarter, '2017-09-30 11:35:00. 100') = 3DATENAME (dayofyear, '2017-09-30 11:35:00. 100') = 2008DATENAME

string in a stringSelect STUFF (' asdf ', 2,0, ' DF ')--Play spaceSelect SPACE (4)--The first occurrence of an index number in a stringSelect CHARINDEX (' A ', ' Dsaf ')--Take the string to the leftSelect Left (' Qwert ', 3)--Right Fetch stringSelect Right (' Qwert ', 3)--Turn capitalSelect UPPER (' ASD ')--Turn lowercaseSelect LOWER (' ASD ') --Date function[Email protected] @DATEFIRST The first day of the week, DW is the @@ 系统 constantSELECT @ @DAT

' Gallery_name ' = ' Youth ',' Mid ' =>4,' Create_time ' =>147258369,' Image ' = ' uploade/image3.jpg '),Array' Gallery_name ' = ' The love of her ',' Mid ' =>5,' Create_time ' =>147258369,' Image ' = ' uploade/image4.jpg '));$where 1= ' gallery_name= ' good world ' or mid=4 and create_time$where 2=array (' Gallery_name ' and ' The Good world ',' Mid ' =>array (' or ', 4),' Create_time ' =>array (' ' Image ' =>array (' like ', '%upload% '),' ID ' =>array (' in ', Array (2,3,4,5)));$order = Array

Paip. program function time performance optimization and SQL statement Optimization Author attilax,1466519819@qq.com Tracking Tool xdebug ..1 Profiler log analysis tool wincachegrind.2 Obtain the complete SQL statement from the code for testing...2 Test SQL statement time...2 Disable

, ' DF ')--Play spaceSelect SPACE (4)--The first occurrence of an index number in a stringSelect CHARINDEX (' A ', ' Dsaf ')--Take the string to the leftSelect Left (' Qwert ', 3)--Right Fetch stringSelect Right (' Qwert ', 3)--Turn capitalSelect UPPER (' ASD ')--Turn lowercaseSelect LOWER (' ASD ')--Date function[Email protected] @DATEFIRST The first day of the week, DW is the @@ 系统 constantSELECT @ @DATEFIRST as ' 1st day ', DATEPART (DW, GETDATE ()

SQL Server String FunctionsString functions are used to perform various operations on characters and binary characters1.ASCII () functionThe ASCII (character_expression) function is used to return the leftmost ASCII code value in a string expression. The parameter character_expression must be a string expression of char or varchar type. Eg:select ASCII (' s '), ASCII ('

Label:get one months of days: first to the date of the last day of the one month, by using the SQL Server Date function day () to get the "days" part of the date Number of days to get February 2008:Select Day (CAST (' 2008-03-01 ' as DateTime)-1) Get the number of days this month: Returns an integer that indicates which day of the month the specified date is. Select Day (DateAdd (Month,1,getdate ()) – Day (

Create FUNCTION InsertComp (@ in varchar (30 ))RETURNS varchar (30)ASBEGINDeclare@ Pos int,@ Count int,@ Result varchar (30 ),@ Len intSet @ result = @ in-- The position before the pointSet @ pos = CHARINDEX ('.', @ result)-1If (@ pos =-1) set @ pos = len (@ result)Set @ count = @ pos-3While (@ count> = 1)BeginSet @ len = len (@ result)-@ countSet @ result = left (@ result, @ count) + ',' + substring (@ result, @ count + 1, @ len)Set @ count = @ count

SQL Server table-valued function and scalar-valued function define the way and call difference SQL stored procedures often need to call some functions to make the process more reasonable, you can also make functions more reusable, but when writing SQL functions you may find

First, the basic concept: SQL functions can contain any number of queries, but the function only returns the result of the last query (which must be a select). In simple cases, returns the first row of the last query result. If the last query does not return any rows, the function returns a null value. If you need this funct