DeLorme XMap 6, Руководство пользователя, Страница: 184 / 437

XMap User Guide
176
date_expression.
IF IF( logical_expression ,
value_if_true ,
value_if_false )
Returns one value if a condition you
specify evaluates to TRUE and
another if it evaluates to FALSE. The
result type is derived from
value_if_true and value_if_false,
which must either be both string or
both numeric. If numeric, then if
either of the values is float, then the
return type is float_expression, and
otherwise it is integer_expression; if
string, then the result type is
string_expression.
IS [NOT]
EMPTY field IS [ NOT ] EMPTY Returns TRUE if the string field field
is empty and FALSE otherwise. NOT
may be use to reverse the sense of
the test. The result type is
logical_expression.
IS [NOT]
NULL field IS [ NOT ] NULL Returns TRUE if field is NULL and
FALSE otherwise. NOT may be use
to reverse the sense of the test. The
result type is logical_expression.
LEN LEN( string_expression ) Returns the length of a string. The
result type is integer_expression.
LEFT LEFT( string_expression ,
number_of_characters ) Return the leftmost
number_of_characters characters of
a string, where
number_of_characters is of type
integer_expression. The result type
is string_expression.
LTRIM LTRIM( string_expression
)
Return a string with spaces removed
from its left end. The result type is
string_expression.
LOWER LOWER( string_expression
)
Returns a string with its letters
converted to lowercase. The result
type is string_expression.
MAX MAX( field ) Return the maximum value of a
field. The result type is the same as
the data type of field.
MID SUBSTRING(
string_expression , start ,
length )
Return the length characters of a
string beginning at start. start and
length are both of type
integer_expression. MID is
synonymous with the SUBSTRING
function. The result type is
string_expression.