Substrings
(start-n:length-n) is an expression that specifies a count of alphanumeric characters from the beginning of a string and a length:
start-n specifies the start of the substring as indicated by n, which is the number of alphanumeric characters from the beginning of a string or referenced field.
length-n specifies the number of alphanumeric characters for the substring as indicated by n. This is the length of the substring.
Tip: For faster searching, add an asterisk to the end of your partial query. Example: cert*