Varchar or nvarchar which is better

You must be logged in to reply to this topic. Login to reply. Post reply. May 17, at pm Q1 can someone tell me the exact difference between varchar and nvarchar in sql server Would I gain any performance improvement by using bit instead of tinyint or integer for Boolean? Q3 Is true-false bit test significantly faster than comparing two dates?

May 18, at am If you are not storing non-english values, stick with vawrchar. May 18, at pm Steve, Is "vawrchar" a typo in your posting? I will be dealing with English character only. About bit: If I have single bit column in my table then probably it won't help to declare it as bit unless sql server store things column by column and not record by record.

Only mutliple of 8 bit can be stored. I will appretiate further insight into this. May 19, at pm The 8 in UTF-8 means it uses 1 byte 8-bits to represent a character in memory. Likewise, UTF uses 16 bits 2 bytes to represent a character. This helps in minimizing character conversion issues. UTF-8 support for varchar data type provides substantial storage savings depending on the character set in use.

For eg, using an UTF-8 enabled collation, changing the column data type from nvarchar 20 to varchar 20 offers a significant drop in storage requirements since nvarchar 20 requires 40 bytes for storage and varchar 20 needs 20 bytes for the same Unicode string.

Important side note — Since this enhancement is still in preview, we can expect more progressions on this front in the near future. Collation in SQL Server defines configurations to determine various rules like case sensitivity, accent sensitivity, sorting, character types and width etc.

Understanding all these properties and how do they work with your data become very important. Collation can be set at server, database, expression or column level. You can read more on Database Collation from here. Real data deals with a mix of data types and it has to be compatible with each other i. SQL Server supports both implicit and explicit conversions.

With an incessant need of formatting and displaying data in the required output, SQL varchar comes really handy. The following script converts two datetime columns to SQL varchar types with style and to display the data in the format yyyy. Also, the SalesAmount column with Money as a data type is converted to varchar and style 3 is applied to display the amount with commas as shown in the screenshot below.

Additionally, say, we would want to see data for the orders placed in the year only, using the CAST function to convert datetime column to varchar data, the string comparison is performed in the WHERE clause. You can also go over SQL convert date to find more information on date conversion formats and styles.

SQL Server stores long string data in the commonly used varchar data type and it becomes helpful to know the expected and maximum lengths of the strings to display the results in the UI. Copy and execute the below code, where we are passing a long string in an unspecified length varchar variable demovarchar and also in another variable with a defined varchar length demovarcharwithcast. In our case, even though the length of the string was 52, it returned 30 as the length as shown in the last result output.

One important point to note here is that when an unspecified length varchar field is created, the default length of such field is 1 shown in red color below. Data types like varchar, char and nvarchar are all used to store string data in SQL Server. This means SQL Server varchar holds only the characters we assign to it and char holds the maximum column space regardless of the string it holds. Because of the fixed field lengths, data is pulled straight from the column without doing any data manipulation and index lookups against varchar are slower than that of char fields.

So in cases where disk size is not an issue, it is recommended to use CHAR. The below example shows how CHAR uses the maximum allotted space to fit in the string passed and how varchar column uses only the needed space. Bottom line is to use the data type that fits our need. That is not accurate. When it comes to data types, what impacts seek vs scan is whether the underlying data types match. The "Table of Differences" is not accurate for variable character data types varchar and nvarchar.

Both have two additional bytes for storage. If your string is 5 chracters, varchar requires 7 bytes for varchar and 12 bytes for nvarchar.

If using varchar max or nvarchar max , an additional 24 bytes is required. I very much disagree with your statement of "use only if you need Unicode support such as the Japanese Kanji or Korean Hangul characters due to storage overhead". This is shortsighted and exactly what leads to problems like the Y2K fiasco. Then, suddenly, we got an overseas customer. Then of course making sure we didn't break anything. However, if the developers had the foresight to just support Unicode from the getgo there would have been no issues.

Yes, Unicode uses more storage space, but storage space is cheap these days. Otherwise, years from now, when your salesmen begin selling outside of the English speaking world you're going to have a daunting refactoring task ahead of you. SQL Server differences of char, nchar, varchar and nvarchar data types. Related Articles. Row sizes exceeding bytes in Sql Handling error converting data type varchar to numeric in SQL Server. Always use the right case for data type names in SQL Server. Popular Articles.

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