I. Scenarios
In SQL Server 2005, there is a table TestDatetime, where the data type of the Dates field is datetime. If you see a table record, what do you first think?
(Figure 1: Data List)
When you see this data, do you think this design is a
I. Scenarios
In SQL Server 2005, there is a table TestDatetime, where the data type of the Dates field is datetime. If you see a table record, what do you first think?
Figure 1: Data List)
When you see this data, do you think this design is a waste
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 this series, we mainly introduce the basics of LINQ to SQL. Because of the powerful nature of LINQ, it has different contents for different data sources, this includes the SQL Server database's LINQ to SQL, the XML document's LINQ to XML, and the
Null semantics and DateTime, linqdatetime of the linq to SQL statement (14)Null Semantics
Note: The first example below describes the query of employees whose ReportsToEmployee is null. The second example uses Nullable . HasValue to query an
SQL Server uses date to represent dates, time to represent times, and datetime and datetime2 to represent dates and times.1, the precision of the second refers to the number of decimal places used to represent 1s:The precision of the datetime data
First, review the syntax format of CONVERT (): convert ([length], [, Style])
Second, here pay attention to the meaning of style: style is the conversion of datatime and smalldatetime data to a string by the SQL Server system provided by the
In the project development process, we often have to do some time-based queries, such as querying the history of the specified time range, but these times are passed from the UI parameters, so we write the SQL statement must use the string
The DB has a time in the array of char types, for example 20151111 12171220000, which now needs to be reduced by 5s, forming a time range and then writing the stored procedure. the idea is to convert the time to datetime first, and then the DateTime
Int
(1). 4 byte storage, the length of the int is 4 bytes, the storage space is less than datatime, the int index storage space is also relatively small, the sorting and the query efficiency is relatively higher a little(2) The readability is
The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion;
products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the
content of the page makes you feel confusing, please write us an email, we will handle the problem
within 5 days after receiving your email.
If you find any instances of plagiarism from the community, please send an email to:
info-contact@alibabacloud.com
and provide relevant evidence. A staff member will contact you within 5 working days.