SQL/MP Reference Manual

HP NonStop SQL/MP Reference Manual—523352-013
L-3
Considerations—LIKE

If the values you compare are both empty strings (that is, strings of zero length),
the LIKE predicate is true.

A blank is compared in the same way as any other character.

If the value of col-name is null or if host-variable or param-name contains
INDICATOR clauses that specify a null value, the LIKE predicate evaluates to null.

You can use only parameters in a prepared dynamic SQL statement or in a
statement you enter through SQLCI.

If you specify NOT, the predicate is true if the value you are comparing does not
match any string to which you compare it, or is not the same length as any string to
which you compare it. 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 “ABC” is equivalent to
NOT (NAME LIKE “ABC”).

You can look for similar values by specifying only a few characters and using these
wild-card characters:
You must specify the wild-card characters (underscore and percent sign) in the
character set associated with the column or unexpected results can occur. These
are the values for the character sets SQL supports:

If you want to search for a string containing a percent sign or underscore, you can
define an escape character (using ESCAPE character) to turn off the special
meaning of percent sign and underscore.
You can specify a character as a host variable, string literal, or a parameter name
for which you supply a one-character value later (for example, ?ESC). If you want
to include a percent sign or underscore in the comparison string, enter the escape
character immediately preceding it. For example, to locate the value A_B, enter:
NAME LIKE "A\_B" ESCAPE "\"
% Percent sign indicates zero or more characters of any type are
acceptable. For example, “%ART%” matches “SMART”, “ARTIFICIAL”,
and “PARTICULAR”, but not “smart”.
_ Underscore indicates any single character is acceptable. For example,
“BOO_” matches “BOOK” or “BOOR”; but not “BOO”, “BOOKLET”, or
“book.”
Character Set Underscore Percent Sign
UNKNOWN HEX 5F HEX 25
ISO99591/9 HEX 5F HEX 25
KANJI HEX8151 HEX 8193
KSC5601 HEX A3DF HEX A3A5