SQL/MX 2.x Reference Manual (H06.04+)

SQL/MX Language Elements

HP NonStop SQL/MX Reference Manual—540440-003

6-93

LIKE Predicate

Considerations for LIKE

Examples of LIKE

The LIKE predicate searches for character strings that match a pattern.

match-value

is a character value expression that specifies the set of strings to search for that

match the pattern.

pattern

is a character value expression that specifies the pattern string for the search.

esc-char-expression

is a character value expression that must evaluate to a single character. The

escape character value is used to turn off the special meaning of percent and

underscore. See Wild Card Characters on page 6-94.

See Character Value Expressions on page 6-37.

Considerations for LIKE

Comparing the Value to the Pattern

The values you compare must be character strings. Lowercase and uppercase letters

are not equivalent. To make lowercase letters match uppercase letters, use the

UPSHIFT function. A blank is compared in the same way as any other character.

When a LIKE Predicate Is True

When you reference a column, the LIKE predicate is true if the pattern matches the

column value. If the value of a column reference is null, the LIKE predicate evaluates

to unknown for that row. If the values you compare are both empty strings (that is,

strings of zero length), the LIKE predicate is true.

Using NOT

If you specify NOT, the predicate is true if the value you are comparing does not match

any string to which you are comparing or is not the same length as any string to which

you are comparing. For example, NAME NOT LIKE '_Z' is true if the string is not two

characters long or the last character is not Z.

In a search condition, the predicate NAME NOT LIKE '_Z' is equivalent to NOT (NAME

LIKE '_Z').

match-value [NOT] LIKE pattern [ESCAPE esc-char-expression]