That's weird, since PADR(ALLTRIM(field),5) and PADR(field,5) gives the same result.

>Brian Based on Tore answer this code shows FULL optimisation in Both cases (VFP9):
>

>SET ANSI OFF
>SET EXACT ON
>CLEAR
>* Turn rushmore reporting on
>SYS(3054,2)
>* Create a test cursor
>CREATE CURSOR test (field C(10))
>INDEX on field TAG field
>INDEX on PADR(ALLTRIM(field),5) TAG field_t
>* Put some data in the cursor
>FOR i = 1 TO 10000
> INSERT INTO test VALUES (SYS(2015))
>ENDFOR
>
>* Determine the last value
>cValue = LEFT(test.field,LEN(ALLTRIM(test.field))-1)
>* Try the untrimmed index
>?"This one works"
>?"---------------------------------"
>SELECT * FROM test WHERE field = cValue INTO CURSOR index
>* Try the trimmed index
>?
>?"This one does not work"
>?"---------------------------------"
>SELECT * FROM test WHERE PADR(ALLTRIM(field),5) = cValue INTO CURSOR noindex
>