sql date calculations

1. First day of the monthSELECT DATEADD (mm, DATEDIFF (Mm,0,getdate ()), 0)2. Last day of the monthSELECT DateAdd (Ms,-3,dateadd (mm, DATEDIFF (M,0,getdate ()) +1, 0))3. The first day of the monthSelect DATEADD (m,-1, DateAdd (mm, DATEDIFF

Working with Dates in PL/SQL (date used in PL/SQL) The previous articles in this introductory PL/SQL series focused on working with strings and numbers in PL/SQL-based applications. without a doubt, strings and numbers are important, but it is

Using date types in PL/SQLThe previous article described the use of strings and numbers in PL/SQL. There is no doubt that strings and numbers are important, but you can be sure that no application is dependent on the date.You need to record events,

Date functionDate functions manipulate Date values (fields of date type), timestamp values (TIMESTAMP, TIMESTAMP with time ZONE, and TIMESTAMP with the fields of the local time ZONE type), and interval values (INTERVAL day to SECOND and INTERVAL

SQL has many built-in functions that can be used for counting and computation.Syntax of the functionThe syntax for the built-in SQL function is:SELECT function (column) from tableTypes of functionsIn SQL, there are several kinds of basic function

Reproduced in this blog, the original blog: http://blog.csdn.net/baiduandxunlei/article/details/9180075CONVERT (Data_type,expression[,style])CONVERT (varchar (10), field name, conversion format)DescriptionThis style is typically in the time type

CONVERT (Data_type,expression[,style])CONVERT (varchar (10), field name, conversion format)DescriptionThis style is typically in the time type (Datetime,smalldatetime) and the string type (Nchar,nvarchar,char,varchar)It is only used when converting

In database application development, we often need to face complex SQL-type calculations, such as row calculation is one of them, such as the monthly sales divided by the last month's sales, the last period, or the monthly sales divided by the same

Introduction On the computerProgramIt is difficult to accurately process the date in. Not only are there obvious (English: January, French: Janvier, German: Januar, etc.) Internationalization requirements, different date systems must also be

Usually, you need to get the current date and calculate some other date, for example, your program may need to judge the first or last day of one months. Most of you probably know how to split dates (year, month, day, etc.), and then just use the