------------------------------------------------------------------------------------------
[BUG/PRB.] VFP 9.0 FIX - THE MAX() AND MIN() FUNCTIONS IN THE SELECT-SQL COMMAND
January 2024
------------------------------------------------------------------------------------------
CCB
1. BUG:
In vfp9 (and vfp6, vfp7, vfp8), we can't use the MAX() and MIN() functions in the SELECT-SQL command,
because there are 2 SQL aggregate functions with the same names.
2. CAUSE:
There are some BUGs in the following code.
3. RESOLUTION:
We can write some code to fix the BUG.
Fun453dd4 :: ; proc near
push ebx ;0x00453dd4 : 53
mov ebx , dword ptr [ edi + 4 ] ;0x00453dd5 : 8b5f04
cmp ebx , 046h ;0x00453dd8 : 83fb46
push ebp ;0x00453ddb : 55
mov ebp , dword ptr [ esp + 16 ] ;0x00453ddc : 8b6c2410
push esi ;0x00453de0 : 56
mov esi , eax ;0x00453de1 : 8bf0
mov dword ptr [ esp + 20 ] , esi ;0x00453de3 : 89742414
je Label5ca4e1 ;0x00453de7 : 0f84f4661700
cmp ebx , 044h ;0x00453ded : 83fb44
je Label5ca4eb ;0x00453df0 : 0f84f5661700
Label453df6 ::
mov byte ptr [esi] , 043h ;0x00453df6 : c60643
inc esi ;0x00453df9 : 46
cmp ebx , 01FCh ;0x00453dfa : 81fbfc010000
mov byte ptr [edi] , 07h ;0x00453e00 : c60707
je Label446aa7 ;0x00453e03 : 0f849e2cffff
Label453e09 ::
pushd 00h ;0x00453e09 : 6a00
pushd 01h ;0x00453e0b : 6a01
pushd 00h ;0x00453e0d : 6a00
push edi ;0x00453e0f : 57
call Fun430428 ;0x00453e10 : e813c6fdff
Label453e15 ::
mov al , byte ptr [edi] ;0x00453e15 : 8a07
cmp al , 04h ;0x00453e17 : 3c04
jne Label453e28 ;0x00453e19 : 750d
cmp dword ptr [ edi + 4 ] , 040BEh ;0x00453e1b : 817f04be400000
je Label5ca508 ;0x00453e22 : 0f84e0661700
Label453e28 ::
cmp al , 07h ;0x00453e28 : 3c07
je Label5ca52d ;0x00453e2a : 0f84fd661700
Label453e30 ::
cmp byte ptr [edi] , 04h ;0x00453e30 : 803f04
jne Label453e3f ;0x00453e33 : 750a
cmp dword ptr [ edi + 4 ] , 03h ;0x00453e35 : 837f0403
je Label5ca53e ;0x00453e39 : 0f84ff661700
Label453e3f ::
mov ecx , dword ptr [ esp + 16 ] ;0x00453e3f : 8b4c2410
and ebp , 0FFFFFFFDh ;0x00453e43 : 83e5fd
push ebp ;0x00453e46 : 55
push ecx ;0x00453e47 : 51
Label453e48 ::
mov ecx , edi ;0x00453e48 : 8bcf
mov edx , esi ;0x00453e4a : 8bd6
call Fun4344bf ;0x00453e4c : e86e06feff
test eax , eax ;0x00453e51 : 85c0
jl Label453e9f ;0x00453e53 : 7c4a
je Label5ca552 ;0x00453e55 : 0f84f7661700
add esi , eax ;0x00453e5b : 03f0
cmp byte ptr [edi] , 07h ;0x00453e5d : 803f07
je Label5ca55d ;0x00453e60 : 0f84f7661700
Label453e66 ::
cmp byte ptr [edi] , 01h ;0x00453e66 : 803f01
jne Label5ca56e ;0x00453e69 : 0f85ff661700
;
; -------------------------------------------------------------------------------
; VFP 9.0 FIX - THE MAX() AND MIN() FUNCTIONS IN THE SELECT-SQL COMMAND
; April 2023
; -------------------------------------------------------------------------------
; CCB
;
; In vfp9, we can't use the MAX() and MIN() functions in the SELECT-SQL command,
; because there are 2 SQL aggregate functions with the same names.
; In VFP Advanced, we can use the MAX() and MIN() functions in the SELECT-SQL command.
;
; 2023/4/11, by ccb
;
cmp dword ptr vfpa_sys9131_data,00h
je Label453e6f
cmp dword ptr [ edi + 4 ] , 07h
jne Label453e6f
cmp ebx , 044h
je Label453e09
cmp ebx , 046h
je Label453e09
cmp ebx , 01FEh
je Label453e6f_max
cmp ebx , 01FDh
je Label453e6f_min
jmp Label453e6f
Label453e6f_max ::
mov ebx , 044h
jmp Label453e09
Label453e6f_min ::
mov ebx , 046h
jmp Label453e09
Label453e6f ::
cmp dword ptr [ edi + 4 ] , 03h ;0x00453e6f : 837f0403
jne Label5ca56e ;0x00453e73 : 0f85f5661700
;
; -------------------------------------------------------------------------------
; VFP 9.0 FIX - THE MAX() AND MIN() FUNCTIONS IN THE SELECT-SQL COMMAND
; April 2023
; -------------------------------------------------------------------------------
; CCB
;
; In vfp9, we can't use the MAX() and MIN() functions in the SELECT-SQL command,
; because there are 2 SQL aggregate functions with the same names.
; In VFP Advanced, we can use the MAX() and MIN() functions in the SELECT-SQL command.
;
; 2023/4/11, by ccb
;
cmp dword ptr vfpa_sys9131_data,00h
je Label453e79
cmp ebx , 044h
je Label453e79_max
cmp ebx , 046h
je Label453e79_min
jmp Label453e79
Label453e79_max ::
Label453e79_min ::
mov byte ptr [esi] , bl
pushd 00h
pushd 01h
pushd 00h
push edi
call Fun430428
jmp Label453e8e
Label453e79 ::
pushd 00h ;0x00453e79 : 6a00
mov byte ptr [esi] , 03h ;0x00453e7b : c60603
pushd 01h ;0x00453e7e : 6a01
mov byte ptr [esi] , 0EAh ;0x00453e80 : c606ea
pushd 00h ;0x00453e83 : 6a00
inc esi ;0x00453e85 : 46
push edi ;0x00453e86 : 57
mov byte ptr [esi] , bl ;0x00453e87 : 881e
call Fun430428 ;0x00453e89 : e89ac5fdff
Label453e8e ::
mov edx , dword ptr [ esp + 16 ] ;0x00453e8e : 8b542410
mov byte ptr [ edx + 16 ] , 00h ;0x00453e92 : c6421000
mov edx , dword ptr [ esp + 20 ] ;0x00453e96 : 8b542414
mov eax , esi ;0x00453e9a : 8bc6
sub eax , edx ;0x00453e9c : 2bc2
inc eax ;0x00453e9e : 40
Label453e9f ::
pop esi ;0x00453e9f : 5e
pop ebp ;0x00453ea0 : 5d
pop ebx ;0x00453ea1 : 5b
ret 08h ;0x00453ea2 : c20800
4. APPLIES TO:
VFP 6.0.8167.0
VFP 6.0.8961.0 (SP5)
VFP 7.0.0.9262
VFP 7.0.0.9465 (SP1)
VFP 8.0.0.2521
VFP 8.0.0.3117 (SP1)
VFP 9.0.0.2412
VFP 9.0.0.3504 (SP1)
VFP 9.0.0.4611 (SP2)
VFP 9.0.0.5015 (SP2)
VFP 9.0.0.5411 (SP2)
VFP 9.0.0.5721 (SP2)
VFP 9.0.0.5815 (SP2)
VFP 9.0.0.6303 (SP2)
VFP 9.0.0.6602 (SP2)
VFP 9.0.0.7423 (SP2)
The bug has been fixed in VFP Advanced.
IMPORTANT NOTE:
In vfp9 (and vfp6, vfp7, vfp8), we can use the MAX[] and MIN[] functions in the SELECT-SQL command, for example,
* please refer to: https://www.foxite.com/archives/bug-or-alzheimer-0000494196.htm
SELECT MAX[x1,x2] AS xmax FROM test INTO CURSOR test_tmp nofilter
SELECT MIN[x1,x2] AS xmin FROM test INTO CURSOR test_tmp nofilter
We can also use the following code:
SELECT IIF(x1>=x2,x1,x2) AS xmax FROM test INTO CURSOR test_tmp nofilter && it is the same as MAX(x1,x2).
SELECT IIF(x1<=x2,x1,x2) AS xmin FROM test INTO CURSOR test_tmp nofilter && it is the same as MIN(x1,x2).
5. REFERENCE WEBSITES:
1, baiyujia.com:
http://www.baiyujia.com
http://www.baiyujia.com/vfpdocuments/f_vfp9fix267.asp
2, foxite.com:
https://www.foxite.com/archives/bug-or-alzheimer-0000494173.htm
6. OTHER:
For reference only, there is no guarantees.
Any questions or suggestions, please send me an email at ccb2000@163.com.
|