Converts an expression from one data type to another.
 
CAST( eExpression AS cDataType [ ( nFieldWidth [, nPrecision] ) ]
   [ NULL | NOT NULL ] )
 

 Parameters 
eExpression 


Specifies a data expression, usually in a SQL statement, that you want to convert to 
another data type. eExpression can be a field, calculated field, or other type of expression. 
cDataType 


Specifies the valid name of or letter representing the target data type name. cDataType 
can also be an expression that evaluates to a valid data type name or letter representing a 
valid data type. 

Note:  
If you specify an expression for cDataType, you must enclose the expression you specify for 
cDataType with parentheses.
 

Some field data types require that you specify a value for nFieldWidth, nPrecision, or both. 
The following table lists values for cDataType and whether nFieldWidth and nPrecision 
apply. 


nFieldWidth 

Specifies the field width for certain data types. Visual FoxPro disregards nFieldWidth for the 
following data types: D, T, I, Y, L, M, G, and W. If nFieldWidth is not specified, default values 
are used, for example, as defined by the CREATE TABLE command. 

nPrecision 
Specifies the number of decimal place precision for certain data types. Visual FoxPro 
disregards nPrecision for the following data types: D, T, I, Y, L, M, G, V, Q, and W. If 
nPrecision is not included for the Numeric or Float data type, the default is zero (0), which is 
no decimal places. If nPrecision is not included for the Double data type, nPrecision defaults 
to the number of decimal place precision set by the SET DECIMALS command. If nPrecision 
is not specified for any other data type, default values are used, for example, as defined by 
the CREATE TABLE command. 

NULL | NOT NULL 


Specifies whether to permit null values in the field. 
Note:  
If one or more fields can contain null values, the maximum number of fields the table can 
contain is reduced from 255 to 254.
 

If NULL or NOT NULL is not specified, it is inherited from the expression. 
 Remarks 
The following table shows conversions supported by the CAST( ) function. The vertical axis 
lists the source data type, and the horizontal axis lists the target data type. The following 
letters describe the level of conversion supported: 

Таблицы не перенести, так как форматирование здесь муторное дкло
If you specify decimal precision, conversions between numeric data types, for example, 
Numeric, Float, Currency, and Double, to Integer data type might result in loss of precision.

For conversions to Character, Varchar, and Varbinary data types, if the specified field width 
is less than that of the original data, Visual FoxPro truncates values to fit the field width. 
For conversions to Character data type, if the specified width is greater than that of the 
original data, Visual FoxPro pads the field with spaces to the right of the value.


Example 
The following example uses the SQL SELECT command to retrieve data from the Product_ID 
field in the Products table from the Visual FoxPro sample database, TestData.dbc. The 
example uses the CAST( ) function to convert the results returned from the expression 
unit_Cost * in_Stock, which have Currency type, as a value with Numeric type with a field 
width of 8 and a decimal precision of 2.


CLEAR ALL
OPEN DATABASE HOME(2) + 'Data\Testdata.dbc'
SELECT Product_ID, CAST(unit_Cost * in_Stock AS N(8,2)) FROM Products