Building Regular Expressions

Characters

Within regular expressions, most characters represent themselves.The only exceptions are the special characters below:

[ ] ( ) | ^ - + * % _ ? { }

... and the escape character, if it is defined.

A regular expression that contains no special characters or escape characters matches only strings that are identical to itself (subject to the collation in use).That is, it functions just like the ‘=’ operator:

'Apple' similar to 'Apple'  -- true
'Apples' similar to 'Apple' -- false
'Apple' similar to 'Apples' -- false
'APPLE' similar to 'Apple'  -- depends on collation