A character‑string literal is a string of characters enclosed in single quotation marks ( ''). To include a single quotation mark in a character‑string literal, precede it with an additional single quotation mark.

The INSERT statements in the following example show embedding quotation marks in character‑string literals:

insert into quote values('unquoted literal');
insert into quote values('''single-quoted literal''');
insert into quote values('"double-quoted literal"');
insert into quote values('O''Hare');select * from quote;
 c1
--
unquoted literal     
'single-quoted literal' 
"double-quoted literal" 
O'Hare
 4 records selected

A character string literal can contain multi‑byte characters in the character set used by the SQL client. Only single‑byte ASCII‑encoded quote marks are valid in the syntax.