Collation, DateTime, SParse Column and XML

Query on Float DataType may return inconsistent result

Qingsong Yao — Sat, 14 Nov 2009 19:27:19 GMT

Let us try following T-SQL script on SQL Server: declare @a float =300000000000000000000000000000000000 select @a + 50 -@a select @a -@a +50 go Guess what is the result? the first is 0 . and the second result is 50 . Floating point data is approximate;...(read more)

Tertiary Collation and the performance impact on order clause

Qingsong Yao — Sat, 14 Nov 2009 19:04:26 GMT

Today, One customer asked about collation SQL_Latin1_General_CP1_CI_AI with non unique nonclustered index we are getting a sort on the query plan. The sample script is: CREATE TABLE TableWithASColumn(ID INT PRIMARY KEY, CharData VARCHAR(100) COLLATE SQL_Latin1_General_CP1_CI_AS)...(read more)

How to make Like Case Sensitive?

Qingsong Yao — Fri, 18 Sep 2009 07:13:34 GMT

Today, I got a question from customer: I have one column (Type: nVarchar) in a table which has data something like this: a1 aa aa2 AB I want to show all the rows which have all the lower case letters in the above mentioned column. The following query...(read more)

Unicode References

Qingsong Yao — Wed, 20 May 2009 08:00:50 GMT

In this article, I recommend several Unicode articles/websites for reference. Note, the list is not yet completed, I will add more entries and make better categorization My blog is a good site for collation issues in SQL Server. Sort it all out . Michael...(read more)

Beta version of collation selecting tool availiable

Qingsong Yao — Sat, 11 Apr 2009 02:04:00 GMT

Hello, Guys Please the attached zip file for the SQL Server collation selection tool. It is written in C#....(read more)

SQL Server and UTF-8 Encoding (1) -True or False

Qingsong Yao — Fri, 10 Apr 2009 08:44:00 GMT

Today, I will start my series of articles about SQL Server and Unicode UTF-8 Encoding. In many times, I found when people ask me about UTF-8, they actually don't understand UTF-8. So today's talk will be quite short. I just clarify some misunderstand....(read more)

What I was doing these days?

Qingsong Yao — Tue, 07 Apr 2009 08:28:00 GMT

In recent days, I am mainly reading test books since I am a Tester, and I need to know more about testing. The good news for people who are interesting in collation topic is that I will have a SQL Server collation select tool available soon. I hope I...(read more)

SQL Server’s Binary Collations

Qingsong Yao — Tue, 07 Apr 2009 06:55:00 GMT

Today, I will discuss SQL Server’s Binary collations. In SQL Server, we have two kinds of binary collations: BIN collation, which has collation name ending with _BIN and BIN2 collation, which has collation name ending with _BIN2. In SQL Server, a string...(read more)

Be aware of comparing unicode constant with varchar column (updated)

Qingsong Yao — Thu, 26 Mar 2009 07:27:00 GMT

Today, I looked for SQL Server JDBC Driver's sendStringParametersAsUnicode, this parameter controls how Unicode String (Java only have Unicode string which is UTF-16 encoding) will be sending to SQL Server. As the name of this parameter indicate, when...(read more)

Is Datetime2 compliant with Daylight Savings Time?

Qingsong Yao — Thu, 12 Mar 2009 08:08:00 GMT

Today, I got following questions: " The documentation states that Datetime2 is unaware of the time zone. Does that still guarantee that when the clock gets adjusted for Daylight Saving Time this will not result in duplicate timestamps? I.e. is Datetime2...(read more)

Why I write so many collation topics?

Qingsong Yao — Wed, 11 Mar 2009 08:10:00 GMT

You may wonder why I keep writing collation topics in my blogs. I found our Books Online topics related to collation is not so clearly enough, and sometime it confuse our reader. I intend to present my idea related to collation in a series of blogs, and...(read more)

Got Collation conflict, How to avoid this?

Qingsong Yao — Wed, 11 Mar 2009 07:48:00 GMT

The best way to avoid SQL Server's collation conflict issue is that avoid have different collations in your database schema. If your server and database have the same collation, you will never see the conflict collation issue. if all string columns in...(read more)

GB18030 Character Set Support in SQL Server

Qingsong Yao — Tue, 24 Feb 2009 09:51:00 GMT

Recently, I got several request related to GB18030 Character Set support in SQL Server. Here is one of the requests: When I try to insert different combination of GB18030 characters in to a varchar column, it gives me unique constraint violation error....(read more)

My recommendation of SQL Server’s Globalization Development

Qingsong Yao — Tue, 24 Feb 2009 09:20:00 GMT

Normal 0 false false false EN-US ZH-CN X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:"";...(read more)

UTF-16 Encoding and SQL Server (4) - String Function Case Study

Qingsong Yao — Fri, 13 Feb 2009 09:32:00 GMT