nchar and nvarchar will take up twice as much storage space, so it may be wise to use them only if you need Unicode support. fromhttp://stackoverflow.com/questions/176514/what-is-the-difference-between-char-nchar-varchar-and-nvarchar-in-sql-server 文中说:varcharcannot store Unicodecharacters...
• 姓名:varchar(255) • 身份号:char(18) • 电话:char(11) • 地址:varchar(255) • 备注:text • 姓:varchar(10) • 名:varchar(10) • 编号:主键 • 姓名:普通索引(注意在区别分度高的字段上加) • 身份证:unique • 电话:unique • 备注:全文索引,借助第三方软件sphinx来运行...
'Server does not support secure connections' error with SMTP mail and SSL 'string.Split(params char[])' has some invalid arguments 'string' does not contain a definition for 'empty' 'System.Threading.ThreadAbortException' occurred in mscorlib.dll...what is the error?how to solve??? 'System...
DIFFERENCE BETWEEN "INSERT INTO" AND UNION IN SQL difference between (WITH [tablename] AS) and (DECLARE @[tablename] TABLE) Difference between APP_NAME() and PROGRAM_NAME() difference between char(13) and char(10) Difference Between DB Log File and Transaction log file Difference between JOI...
Except the above statement, there is no difference between AND and &&. Let us look at all the conditions. The result of AND and && will always be either 1 or 0. As we know the AND and && both are logical operators, if there are more than one operand and any one of them has valu...
[student_code] [varchar](5) NOT NULL, [student_grade] [char](2) NOT NULL, [SchoolID] [int] NOT NULL, CONSTRAINT [PK_tblStudent] PRIMARY KEY CLUSTERED ( [ID] ASC)) GO ALTER TABLE [dbo].[tblStudent] WITH CHECK ADD CONSTRAINT [FK_tblStudent_tblSchool] FOREIGN KEY([SchoolID]) ...
Hello all, today, I am going to share an interesting SQL Server interview question, which will not only help you in your interview but also in your day-to-day work. It explains one of the critical concepts of SQL Server, the difference between VARCHAR and CHAR data type. I am sure, ...
l_sql VARCHAR2(100); BEGIN l_start := dbms_utility.get_time; FOR j IN 1..20 LOOP EXECUTE IMMEDIATE 'SELECT count(*) FROM t' INTO l_dummy; END LOOP; l_stop := dbms_utility.get_time; dbms_output.put_line('COUNT星20次的时光是:'||to_char((l_stop-l_start)/100,'0.99')); ...
Many factors cause the PostgreSQL server versus the SQL server situation. This portion of the article sheds light on things to consider when choosing between the two products. History and Release Updates PostgreSQL Originating from the University of California, Berkeley in 1986, PostgreSQL made its...
l_sql VARCHAR2(100); BEGIN l_start := dbms_utility.get_time; FOR j IN 1..20 LOOP EXECUTE IMMEDIATE 'SELECT count(*) FROM t' INTO l_dummy; END LOOP; l_stop := dbms_utility.get_time; dbms_output.put_line('COUNT星20次的时间是:'||to_char((l_stop-l_start)/100,'0.99')); ...