|The PostgreSQL 9.0 Reference Manual - Volume 1A - SQL Language Reference
by The PostgreSQL Global Development Group
Paperback (6"x9"), 454 pages
RRP £14.95 ($19.95)
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An operator name is a sequence of up to
(63 by default) characters from the following list:
+ - * / < > = ~ ! @ # % ^ & | ` ?
There are a few restrictions on operator names, however:
/*cannot appear anywhere in an operator name, since they will be taken as the start of a comment.
A multiple-character operator name cannot end in
-, unless the name also contains at least one of these characters:
~ ! @ # % ^ & | ` ?For example,
@-is an allowed operator name, but
*-is not. This restriction allows PostgreSQL to parse SQL-compliant queries without requiring spaces between tokens.
When working with non-SQL-standard operator names, you will usually
need to separate adjacent operators with spaces to avoid ambiguity.
For example, if you have defined a left unary operator named
you cannot write
X*@Y; you must write
X* @Y to ensure that
PostgreSQL reads it as two operator names
|ISBN 9781906966041||The PostgreSQL 9.0 Reference Manual - Volume 1A - SQL Language Reference||See the print edition|