TCustomClientDataSet.Filter Property

Specifies the text of the current filter.

Pascal

property Filter: string;

C++

__property AnsiString Filter;

Description

Use Filter to specify a dataset filter. When filtering is applied to a client dataset, only the records that meet a filter's conditions are available to an application. Filter contains the string that describes the filter condition. The Filter property is effective only if the Filtered property is set to True. In this case, if you change the Filter property, the filter is automatically updated.

The following table lists all the operators that can be used when defining a filter, as well as usage examples.

Operator or function comparisons	Example	Comment
=	State = 'CA'
<>	State <> 'CA'
>=	DateEntered >= '1/1/1998'
<=	Total <= 100,000
>	Percentile > 50
<	Field1 < Field2
BLANK	State <> 'CA' or State = BLANK	Blank records do not appear unless explicitly included in the filter.
IS NULL	Field1 IS NULL
IS NOT NULL	Field1 IS NOT NULL.
Logical operators
and	State = 'CA' and Country = 'US'
or	State = 'CA' or State = 'MA'
not	not (State = 'CA')
Arithmetic operators
+	Total + 5 > 100	Applies to numbers, strings, or date (time).
-	Field1 - 7 <> 10	Applies to numbers, dates, or date (time).
*	Discount * 100 > 20	Applies to numbers only.
/	Discount > Total / 5	Applies to numbers only.
String functions
Upper	Upper(Field1) = 'ALWAYS'
Lower	Lower(Field1 + Field2) = 'josp'
Substring	Substring(DateString,8) = '1998' \| Substring(DateString,1,3) = 'JAN'	Extracts a substring from the string named in the first argument, starting at the position specified in the second argument. The third argument represents the number of characters copied from the string to the substring. If the third argument is missing, the string is copied from the specified position until the end.
Trim	Trim(Field1 + Field2) \| Trim(Field1, '-')	Removes spaces from the beginning and the end of a string.
TrimLeft	TrimLeft(StringField) \| TrimLeft(Field1, '$') <> ''	Removes spaces from the beginning of a string.
TrimRight	TrimRight(StringField) \| TrimRight(Field1, '.') <> ''	Removes spaces from the end of a string.
DateTime functions
Year	Year(DateField) = 2000
Month	Month(DateField) <> 12
Day	Day(DateField) = 1
Hour	Hour(DateField) < 16
Minute	Minute(DateField) = 0
Second	Second(DateField) = 30
GetDate	GetDate - DateField > 7	Represents current date and time.
Date	DateField = Date(GetDate)	Returns the date portion of a date-time value.
Time	TimeField > Time(GetDate)	Returns the time portion of a date-time value.
Miscellaneous
Like	Memo LIKE '%filters%'	Works like SQL-92 without the ESC clause. When applied to BLOB fields, FilterOptions determines whether case is considered.
In	Day(DateField) in (1,7)	Works like SQL-92. Second argument is a list of values all with the same type.
*	State = 'M*'	Wildcard for partial comparisons.