MATCHES operator

Compares a character expression to a pattern and evaluates to a TRUE value if the expression satisfies the pattern criteria.

Syntax 

 

expression MATCHES pattern

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.

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.

See also 

BEGINS operator