diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/func.sgml | 12 |
1 files changed, 4 insertions, 8 deletions
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index d2b0b059e65..7efc81936ab 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -3120,19 +3120,15 @@ SELECT NOT(ROW(table.*) IS NOT NULL) FROM TABLE; -- detect at least one null in <para> Performs case folding of the input string according to the collation. Case folding is similar to case conversion, but the purpose of case - folding is to facilitate case-insensitive comparison of strings, + folding is to facilitate case-insensitive matching of strings, whereas the purpose of case conversion is to convert to a particular cased form. This function can only be used when the server encoding is <literal>UTF8</literal>. </para> <para> - Ordinarily, case folding simply converts to lowercase, but there are a - few notable exceptions depending on the collation. For instance, the - character <literal>Σ</literal> (U+03A3) has two lowercase forms: - <literal>σ</literal> (U+03C3) and <literal>ς</literal> (U+03C2); case - folding in the <literal>PG_C_UTF8</literal> collation maps all three - forms to <literal>σ</literal>. Additionally, the result is not - necessarily lowercase; some characters may be folded to uppercase. + Ordinarily, case folding simply converts to lowercase, but there may + be exceptions depending on the collation. For instance, some + characters have more than two lowercase variants, or fold to uppercase. </para> <para> Case folding may change the length of the string. For instance, in |