SQL Server string processing functions Daquan

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--=====================================║cast function conversion ║

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The CAST () function syntax is as follows:

--CAST (<expression> as <data_ type>[length])

/*

"0", convert also provides a rich style for date conversion, cast only for normal date conversion

"1", Data_type is the data type defined for the SQL Server system, and the user-defined data type cannot be used here.

2, length specifies the length of the data, and the default value is 30.

*/

--★ Instance ★

Select CONVERT (nvarchar,123)--Return 123

Select N ' Age: ' +convert (nvarchar,23)

--Return Age: 23 (Note: If you want to display Chinese correctly in the results, you need to precede the given string with N, plus n to make the database recognize Unicode characters)

Select convert (nvarchar, getdate ())

--Return to 10:21pm

Select convert (nvarchar, GETDATE (), 101)

--Back to 04/28/2009

Select convert (nvarchar, getdate (), 120)

--Return 2009-04-28 12:22:21

Select convert (nvarchar), GETDATE (), 120)

--Back to 2009-04-28

--╔══════════╗

--=================================║convert function conversion ║

--╚══════════╝

The-CONVERT () function syntax is as follows:

--CONVERT (<data_ type>[length], <expression> [, Style])

/*

"0", convert also provides a rich style for date conversion, cast only for normal date conversion

"1", Data_type is the data type defined for the SQL Server system, and the user-defined data type cannot be used here.

2, length specifies the length of the data, and the default value is 30.

*/

--★ Instance ★

Select CAST (123 as nvarchar)--return 123

Select N ' Age: ' +cast (nvarchar)--return Age: 23

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--====================================║ parameter Description ║

--╚══════════╝

/*

3. Convert char or varchar type to an integer type such as int or samllint, and the result must be a number with a plus sign (+) or minus (-).

4, the text type to char or varchar type conversions to a maximum of 8,000 characters, that is, the char or varchar data type is the maximum length.

5. The image type stores data converted to binary or varbinary type with a maximum of 8,000 characters.

6, convert the integer value to Money or smallmoney type, according to the definition of the country's currency units to deal with, such as RMB, USD, GBP and so on.

7. A bit type conversion converts a non-0 value to 1 and is still stored as a bit type.

8. Attempts to convert to a different length of data type will truncate the conversion value and display "+" after the value is converted to identify that this truncation has occurred.

*/

SQL Server string processing functions Daquan