Compares a character expression to a pattern
and evaluates to a TRUE value if the expression satisfies the pattern
criteria.
Syntax
expression MATCHES pattern
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-
expression
- A CHARACTER or LONGCHAR expression that you want to check to
see if it conforms with the pattern.
-
pattern
-
A character expression that you want to match with the string. This
can include a constant, field name, variable name, or expression whose
value is a character.
The pattern can
contain wildcard characters: a period (.) in a particular position
indicates that any single character is acceptable in that position;
an asterisk (*) indicates that any group of characters is acceptable,
including a null group of characters.
Example
This
procedure displays customer information for all Customers whose Address ends
in St. The procedure does not use an index for the Customer search
in r-match.p.
r-match.p
FOR EACH Customer NO-LOCK WHERE Customer.Address MATCHES("*St"):
DISPLAY Customer.Name Customer.Address Customer.City Customer.State
Customer.Country.
END.
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Notes
- MATCHES
does not use index information when performing a comparison; it
always scans the entire data table.
- MATCHES does not ignore trailing blanks as does the equal (EQ) comparison
operator. Thus, "abc" does not match "abc "
although they are considered equal.
- Most character comparisons are case insensitive in ABL. By default, all
characters are converted to uppercase prior to comparisons. However, you
can define fields and variables as case sensitive (although it is
not advised, unless strict ANSI SQL adherence is required). If the expression preceding
the MATCHES keyword is a field or variable defined as case sensitive,
the comparison is case sensitive. In a case-sensitive comparison
"SMITH" does not equal "Smith".
- MATCHES converts a LONGCHAR variable value to -cpinternal prior
to comparison. The variable must convert without error, or the AVM
raises a run-time error.
- You cannot use MATCHES to compare one CLOB field to another.
- To specify either an asterisk ( * ), as a literal character
rather than a wildcard character in the pattern, or a period ( .
) as a literal character, you must enter a tilde (~) before the
character. However, if you specify the match pattern as a literal
quoted string in a procedure file, you must enter each tilde as
a double tilde ( ~ ~ ). The first tilde escapes the
- second tilde, so that the AVM interprets the second tilde as
a tilde for the match pattern. For example, the result of "*a.b"
MATCHES "~~*a~~.b" is TRUE.
- The MATCHES function is double-byte enabled. Both the specified expression and pattern arguments
can contain double-byte characters.
