On 4/9/08, Richard Klein <[EMAIL PROTECTED]> wrote:
> > Richard Klein <[EMAIL PROTECTED]>
> > wrote:
> >> One question: I thought that the '\' character is not part of the
> >> SQL standard. (That's why I specified '/' instead as my ESCAPE
> >> character).
> >
> > I'm not sure I understand. You can use any character as an escape
> > character. E.g. LIKE '2!_%' ESCAPE '!'. A backslash is as good as any.
> >
> > Igor Tandetnik
>
> I'm a SQL newbie, so I may very well be wrong about this ...
>
> My understanding is that you can use any legal SQL character as an escape
> character, but that a backslash is not a legal SQL character.
>
> I got this impression from a sentence I read on the SQLite website (in
> the description of literal numeric values):
>
> "C-style escapes using the backslash character are not supported because
> they are not standard SQL."
>
If I understand correctly Igor Tandetnik's comment "A backslash is as
good as any.", in the above quote the phrase "they are not standard
SQL" refers to C-style escapes and not to the use of the backslash
character as an escape defined with ESCAPE.
LIKE '2\_%'
is not valid.
LIKE '2\_%' ESCAPE '\'
is valid.
Robert Wishlaw
> So then I checked the spec, and found syntax definitions (reproduced at
> the end of this email) that do seem to confirm that backslash ('\') is
> not a legal SQL language character.
>
> I haven't checked to see whether SQLite accepts backslash as an escape
> character.
>
> - Richard Klein
>
> ==========================================================================
>
> <SQL language character> ::=
> <simple Latin letter>
> | <digit>
> | <SQL special character>
>
> <simple Latin letter> ::=
> <simple Latin upper case letter>
> | <simple Latin lower case letter>
>
> <simple Latin upper case letter> ::=
> A | B | C | D | E | F | G | H | I | J | K | L | M | N |
> O
> | P | Q | R | S | T | U | V | W | X | Y | Z
>
> <simple Latin lower case letter> ::=
> a | b | c | d | e | f | g | h | i | j | k | l | m | n |
> o
> | p | q | r | s | t | u | v | w | x | y | z
>
> <digit> ::=
> 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
>
> <SQL special character> ::=
> <space>
> | <double quote>
> | <percent>
> | <ampersand>
> | <quote>
> | <left paren>
> | <right paren>
> | <asterisk>
> | <plus sign>
> | <comma>
> | <minus sign>
> | <period>
> | <solidus>
> | <colon>
> | <semicolon>
> | <less than operator>
> | <equals operator>
> | <greater than operator>
> | <question mark>
> | <underscore>
> | <vertical bar>
>
> <space> ::= !! space character in character set in use
>
> <double quote> ::= "
>
> <percent> ::= %
>
> <ampersand> ::= &
>
> <quote> ::= '
>
> <left paren> ::= (
>
> <right paren> ::= )
>
> <asterisk> ::= *
>
> <plus sign> ::= +
>
> <comma> ::= ,
>
> <minus sign> ::= -
>
> <period> ::= .
>
> <solidus> ::= /
>
> <colon> ::= :
>
> <semicolon> ::= ;
>
> <less than operator> ::= <
>
> <equals operator> ::= =
>
> <greater than operator> ::= >
>
> <question mark> ::= ?
>
> <left bracket> ::= [
>
> <right bracket> ::= ]
>
> <underscore> ::= _
>
> <vertical bar> ::= |
>
>
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