求教CONVERT()和NUMERIC()函数的用法

[fys_syf]

[fys_syf]

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[killerdanny]

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CONVERT function [Data type conversion]

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Function
Returns an expression converted to a supplied data type.

Syntax
CONVERT ( data type, expression [ , format-style ] )

Parameters
data type The data type to which the expression will be converted.

expression The expression to be converted.

format-style For converting strings to date or time data types and vice versa, the format-style is a style code number that describes the date format string to be used. The values of the format-style argument have the following meanings:

Without century (yy)
With century (yyyy)
Output

-
0 or 100
mmm dd yyyy hh:nn:ss:sss AM (or PM)

1
101
mm/dd/yy[yy]

2
102
[yy]yy.mm.dd

3
103
dd/mm/yy[yy]

4
104
dd.mm.yy[yy]

5
105
dd-mm-yy[yy]

6
106
dd mmm yy[yy]

7
107
mmm dd, yy[yy]

8
108
hh:nn:ss

-
9 or 109
mmm dd yyyy hh:nn:ss:sssAM (or PM)

10
110
mm-dd-yy[yy]

11
111
[yy]yy/mm/dd

12
112
[yy]yymmdd

13
113
dd mmm yyy hh:nn:ss:sss (24 hour clock, Europe default + milliseconds, 4-digit year )

14
114
hh:nn:ss:sss (24 hour clock)

20
120
yyyy-mm-dd hh:nn:ss:sss (24-hour clock, ODBC canonical, 4-digit year)

21
121
yyyy-mm-dd hh:nn:ss.sss (24 hour clock, ODBC canonical with milliseconds, 4-digit year )



If no format-style argument is provided, Style Code 0 is used.

Examples
The following statements illustrate the use of format styles:

SELECT CONVERT( CHAR( 20 ), order_date, 104 )
FROM sales_order
order_date

16.03.1993

20.03.1993

23.03.1993

25.03.1993

...



SELECT CONVERT( CHAR( 20 ), order_date, 7 )
FROM sales_order
order_date

mar 16, 93

mar 20, 93

mar 23, 93

mar 25, 93

...



The following statement illustrates conversion to an integer, and returns the value 5:

SELECT CONVERT( integer, 5.2 )
Standards and compatibility
SQL/92 Vendor extension.

Sybase Compatible with Adaptive Server Enterprise.