Oracle Regular Expressions Pocket Reference

Name

[= =] (Equivalence Class) — Specifies an equivalence class

Synopsis

Use [= and =] to surround a letter when you want to match all accented and unaccented versions of that letter. The resulting equivalence class reference must always be within a bracket expression. For example:

SELECT REGEXP_SUBSTR('eéëèÉËÈE' '[[=É=]]+') 
FROM dual;

eéëèÉËÈE

SELECT REGEXP_SUBSTR('eéëèÉËÈE', '[[=e=]]+') 
FROM dual;

eéëèÉËÈE

It doesn’t matter which version of a letter you specify between the [= and =]. All equivalent accented and unaccented letters, whether upper- or lowercase, will match.

Note

NLS_SORT determines which characters are considered to be equivalent. Thus, equivalence can be determined appropriately for whatever language you are using.