T-SQL Data Types (Quick Overview)
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This document discusses data types in databases. It describes numeric, character, temporal, and miscellaneous data types. It also covers precision, scale, length, custom data types, special column types like identity and timestamp columns. The document explains CAST and CONVERT functions that explicitly convert data between types and provides syntax examples. It demonstrates converting date/time values to different formats and casting between different data types.
![CAST and CONVERT: Syntax
CAST ( expression AS data_type )
CONVERT ( data_type [ ( length ) ] , expression [ , style ] )](https://image.slidesharecdn.com/sql-datatypesv1-131202085531-phpapp01/85/T-SQL-Data-Types-Quick-Overview-10-320.jpg)
T-SQL Data Types (Quick Overview)
- 1. DATA TYPES VERSION 1.0 By Naji El Kotob
- 2. Data Type? Indicates the type of data the field will contain.
- 3. Data Types Numeric data types Character data types Temporal (date and/or time) data types Miscellaneous data types
- 4. Precision, Scale, and Length Precision is the number of digits in a number. Scale is the number of digits to the right of the decimal point in a number. For example, the number 123.45 has a precision of 5 and a scale of 2.
- 5. Custom Data Type (Alias) CREATE TYPE dbo.ProjectCode FROM char(6) NOT NULL
- 6. Special Column Types Computed columns Identity columns An Identity column is often used for primary key values UniqueIdentifier columns Virtual columns that are not physically stored in the table Guaranteed to be universally unique TimeStamp columns Guaranteed to be unique within a database
- 7. Converts an expression of one data type to another.
- 8. Source: MSDN
- 9. CAST and CONVERT Explicitly converts an expression of one data type to another.
- 10. CAST and CONVERT: Syntax CAST ( expression AS data_type ) CONVERT ( data_type [ ( length ) ] , expression [ , style ] )
- 11. CAST and CONVERT: DEMO
- 12. PRINT 'Date/time in format MON DD YYYY HH:MI AM (OR PM): ' + CONVERT(CHAR(19),GETDATE()) PRINT '6) Date/time in format DD MON YYYY HH:MM:SS:MMM(24H): ' + CONVERT(CHAR(24),GETDATE(),113)
- 13. DECLARE @d DATETIME SET @d = '2008-02-09 10:31 PM' -- Length 19 SELECT REPLACE(CONVERT(CHAR(16),@d,120),'-','/')
- 14. DECLARE @d DATETIME SET @d = '2008-02-09 10:31 PM' SELECT DATENAME(DAY,@d)
- 15. DECLARE @id char(4) SET @id = '123' SET @id = CAST(@id AS int) + 1 SELECT @id
- 16. SELECT CAST(10.6496 AS int)
- 17. SELECT CAST(15.279769 AS money)
- 18. References Data Types http://technet.microsoft.com/enus/library/ms187752.aspx Cast and Convert http://msdn.microsoft.com/enus/library/ms187928.aspx