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Changes to literals

Full SQL standard character string literal syntax

Adriano dos Santos Fernandes

Tracker ticket: #5589

The syntax of character string literals was changed to support the full SQL standard syntax.This means a literal can be “interrupted” by whitespace or a comment.This can be used, for example, to break up a long literal over several lines, or provide inline comments.

<character string literal> ::=
  [ <introducer> <character set specification> ]
    <quote> [ <character representation>... ] <quote>
    [ { <separator> <quote> [ <character representation>... ] <quote> }... ]

<separator> ::=
  { <comment> | <white space> }...
— ISO/IEC 9075-2:2016 SQL - Part 2: Foundation
Examples
-- whitespace between literal
select 'ab'
       'cd'
from RDB$DATABASE;
-- output: 'abcd'

-- comment and whitespace between literal
select 'ab' /* comment */ 'cd'
from RDB$DATABASE;
-- output: 'abcd'

docnext count = 1

Full SQL standard binary string literal syntax

Adriano dos Santos Fernandes

Tracker ticket: #5588

The syntax of binary string literals was changed to support the full SQL standard syntax.This means a literal can contain spaces to separate hexadecimal characters, and it can be “interrupted” by whitespace or a comment.This can be used, for example, to make the hex string more readable by grouping characters, or to break up a long literal over several lines, or provide inline comments.

<binary string literal> ::=
  X <quote> [ <space>... ] [ { <hexit> [ <space>... ] <hexit> [ <space>... ] }... ] <quote>
    [ { <separator> <quote> [ <space>... ] [ { <hexit> [ <space>... ]
    <hexit> [ <space>... ] }... ] <quote> }... ]
— ISO/IEC 9075-2:2016 SQL - Part 2: Foundation
Examples
-- Group per byte (whitespace inside literal)
select _win1252 x'42 49 4e 41 52 59'
from RDB$DATABASE;
-- output: BINARY

-- whitespace between literal
select _win1252 x'42494e'
                 '415259'
from RDB$DATABASE;
-- output: BINARY
Note

The usage of the _win1252 introducer in above example is a non-standard extension and equivalent to an explicit cast to a CHAR of appropriate length with character set WIN1252.