Подскажите, что означает оператор FIND('-')

[IGG]

This...
Tells the system to search for...

'='
A record that equals the key values (default)

'>'
A record that is larger than the key values

'<'
A record that is less the key values

'+'
The last record in the table ('+' can only be used alone)

'-'
The first record in the table ('-' can only be used alone)