Resultat de requète sql sur php !

Bonjour,

N'étant pas très bon programmeur, je suis actuellement confronté à un soucis ! :
je souhaite à l'aide de ce script vérifier d'un utilisateur n'est pas déjà dans la bdd
je fais donc un :
SELECT count(*) FROM users WHERE mail='" . $mail ."
pour compter le nombre de ligne qui comporte c'est adresse
si c'est différent de 0 l'utilisateur est dajà dans la base et je lui demande de s'authentifier
sinon on poursuit le script...

le résultat est stocké dans la variable $result que je teste par if($result<>"0") mais a priori c'est là que sa bloque....enfin je pense....

Une idée ?

code si dessous.

function Verifierusers($mail,$connexion)
{
$requeteuser = "SELECT count(*) FROM users WHERE mail='" . $mail ."'";

$result = ExecRequete ($requeteuser, $connexion);
if($result<>"0")
return true;
else
return false;
}

$adresse=htmlentities($_POST['mail']);
if(Verifierusers($adresse,$connexion))
echo '<p>Vous avez déjà un compte... merci de vous identifier</p>';
exit;
else
echo '<p>Votre adresse est valide.</p>';

$verifuser = Verifierusers ( $_POST[mail],$connexion);

Cordialement

Configuration: Computer
Processor	AMD Athlon(tm) 64 Processor 3000+
Memory	1029MB (560MB used)
Operating System	Debian GNU/Linux squeeze/sid
User Name	administrateur (administrateur)
Date/Time	ven 03 avr 2009 13:10:08 CEST
Display
Resolution	1280x1024 pixels
OpenGL Renderer	Mesa DRI R200 20060602 AGP 8x TCL
X11 Vendor	The X.Org Foundation
Multimedia
Audio Adapter	ICH - SiS SI7012
Audio Adapter	USB-Audio - USB Camera
Input Devices
Macintosh mouse button emulation	
AT Translated Set 2 keyboard	
HID 04b3:310b	
Power Button (FF)	
Power Button (CM)	
Sleep Button (CM)	
PC Speaker	
cx88 IR (Leadtek Winfast 2000XP	
Printers
No printers found	
IDE Disks
MAXTOR STM3160812A	
DVD-ROM BDV316E	
LITE-ON DVDRW SOHW-1633S	
SCSI Disks
IC USB Storage-CFC	
IC USB Storage-SMC	
IC USB Storage-MMC	
IC USB Storage-MSC	
Operating System
Version
Kernel	Linux 2.6.26-1-amd64 (x86_64)
Compiled	#1 SMP Fri Mar 13 17:46:45 UTC 2009
C Library	GNU C Library version 2.9 (stable)
Default C Compiler	GNU C Compiler version 4.3.3 (Debian 4.3.3-5)
Distribution	Debian GNU/Linux squeeze/sid
Current Session
Computer Name	ns
User Name	administrateur (administrateur)
Home Directory	/home/administrateur
Misc
Uptime	1 hour, 35 minutes
Load Average	0,00, 0,00, 0,00
Kernel Modules
Loaded Modules
ppdev	
lp	
radeon	ATI Radeon
drm	DRM shared core routines
cpufreq_powersave	CPUfreq policy governor 'powersave'
cpufreq_conservative	'cpufreq_conservative' - A dynamic cpufreq governor for Low Latency Frequency Transition capable processors optimised for use in a battery environment
cpufreq_userspace	CPUfreq policy governor 'userspace'
cpufreq_stats	'cpufreq_stats' - A driver to export cpufreq stats through sysfs filesystem
cpufreq_ondemand	'cpufreq_ondemand' - A dynamic cpufreq governor for Low Latency Frequency Transition capable processors
freq_table	CPUfreq frequency table helpers
ipv6	IPv6 protocol stack for Linux
sbp2	IEEE-1394 SBP-2 protocol driver
loop	
tuner_simple	Simple 4-control-bytes style tuner driver
tuner_types	Simple tuner device type database
tea5767	Philips TEA5767 FM tuner driver
tda9887	
tda8290	Philips/NXP TDA8290/TDA8295 analog IF demodulator driver
tuner	device driver for various TV and TV+FM radio tuners
cx8800	v4l2 driver module for cx2388x based TV cards
cx88xx	v4l2 driver module for cx2388x based TV cards
ir_common	
i2c_algo_bit	I2C-Bus bit-banging algorithm
tveeprom	i2c Hauppauge eeprom decoder driver
compat_ioctl32	
snd_intel8x0	Intel 82801AA,82901AB,i810,i820,i830,i840,i845,MX440; SiS 7012; Ali 5455
videodev	Device registrar for Video4Linux drivers v2
snd_ac97_codec	Universal interface for Audio Codec '97
v4l1_compat	v4l(1) compatibility layer for v4l2 drivers.
ac97_bus	
v4l2_common	misc helper functions for v4l2 device drivers
snd_usb_audio	USB Audio
snd_usb_lib	USB Audio/MIDI helper module
snd_pcm_oss	PCM OSS emulation for ALSA.
snd_mixer_oss	Mixer OSS emulation for ALSA.
i2c_core	I2C-Bus main module
snd_hwdep	Hardware dependent layer
snd_pcm	Midlevel PCM code for ALSA.
videobuf_dma_sg	helper module to manage video4linux dma sg buffers
videobuf_core	helper module to manage video4linux buffers
snd_seq_dummy	ALSA sequencer MIDI-through client
snd_seq_oss	OSS-compatible sequencer module
btcx_risc	some code shared by bttv and cx88xx drivers
k8temp	AMD K8 core temperature monitor
snd_seq_midi	Advanced Linux Sound Architecture sequencer MIDI synth.
snd_rawmidi	Midlevel RawMidi code for ALSA.
snd_seq_midi_event	MIDI byte <-> sequencer event coder
shpchp	Standard Hot Plug PCI Controller Driver
pci_hotplug	PCI Hot Plug PCI Core
snd_seq	Advanced Linux Sound Architecture sequencer.
pcspkr	PC Speaker beeper driver
snd_timer	ALSA timer interface
snd_seq_device	ALSA sequencer device management
parport_pc	PC-style parallel port driver
parport	
snd	Advanced Linux Sound Architecture driver for soundcards.
soundcore	Core sound module
snd_page_alloc	Memory allocator for ALSA system.
led_class	LED Class Interface
evdev	Input driver event char devices
button	ACPI Button Driver
wmi	ACPI-WMI Mapping Driver
sd_mod	SCSI disk (sd) driver
usb_storage	USB Mass Storage driver for Linux
usbhid	USB HID core driver
hid	
ff_memless	Force feedback support for memoryless devices
ext3	Second Extended Filesystem with journaling extensions
jbd	
mbcache	Meta block cache (for extended attributes)
ide_cd_mod	ATAPI CD-ROM Driver
cdrom	
ide_disk	ATA DISK Driver
ata_generic	low-level driver for generic ATA
libata	Library module for ATA devices
scsi_mod	SCSI core
dock	ACPI Dock Station Driver
ohci_hcd	2006 August 04 USB 1.1 'Open' Host Controller (OHCI) Driver
ide_pci_generic	PCI driver module for generic PCI IDE
floppy	
ohci1394	Driver for PCI OHCI IEEE-1394 controllers
ieee1394	
sis900	SiS 900 PCI Fast Ethernet driver
mii	MII hardware support library
ehci_hcd	10 Dec 2004 USB 2.0 'Enhanced' Host Controller (EHCI) Driver
sis5513	PCI driver module for SIS IDE
ide_core	
thermal	ACPI Thermal Zone Driver
processor	ACPI Processor Driver
fan	ACPI Fan Driver
thermal_sys	Generic thermal management sysfs support

Processor
Name	AMD Athlon(tm) 64 Processor 3000+
Family, model, stepping	15, 4, 10 (AMD Opteron/Athlon64/FX)
Vendor	AuthenticAMD
Configuration
Cache Size	512kb
Frequency	1995,00MHz
BogoMIPS	3993,00
Byte Order	Little Endian
Features
FDIV Bug	no
HLT Bug	no
F00F Bug	no
Coma Bug	no
Has FPU	yes
Cache
Level 1 (Data)	2-way set-associative, 512 sets, 64KB size
Level 1 (Instruction)	2-way set-associative, 512 sets, 64KB size
Level 2 (Unified)	16-way set-associative, 512 sets, 512KB size
Capabilities
fpu	Floating Point Unit
vme	Virtual 86 Mode Extension
de	Debug Extensions - I/O breakpoints
pse	Page Size Extensions (4MB pages)
tsc	Time Stamp Counter and RDTSC instruction
msr	Model Specific Registers
pae	Physical Address Extensions
mce	Machine Check Architeture
cx8	CMPXCHG8 instruction
apic	Advanced Programmable Interrupt Controller
sep	Fast System Call (SYSENTER/SYSEXIT)
mtrr	Memory Type Range Registers
pge	Page Global Enable
mca	Machine Check Architecture
cmov	Conditional Move instruction
pat	Page Attribute Table
pse36	36bit Page Size Extensions
clflush	Cache Line Flush instruction
mmx	MMX technology
fxsr	FXSAVE and FXRSTOR instructions
sse	SSE instructions
sse2	SSE2 (WNI) instructions
syscall	SYSCALL and SYSEXIT instructions
nx	No-execute Page Protection
mmxext	Extended MMX Technology
lm	LAHF/SAHF in long mode
3dnowext	Extended 3DNow! Technology
3dnow	3DNow! Technology
up	smp kernel running on up
rep_good	rep microcode works well on this CPU
Memory
Memory
Total Memory	1029428 kB
Free Memory	22592 kB
Buffers	35560 kB
Cached	446340 kB
Cached Swap	8 kB
Active	597848 kB
Inactive	317920 kB
Virtual Memory	730948 kB
Free Virtual Memory	730788 kB
Dirty	14388 kB
Writeback	0 kB
AnonPages	433884 kB
Mapped	70764 kB
Slab	54080 kB
SReclaimable	44176 kB
SUnreclaim	9904 kB
PageTables	14316 kB
NFS_Unstable	0 kB
Bounce	0 kB
WritebackTmp	0 kB
CommitLimit	1245660 kB
Committed_AS	844652 kB
VmallocTotal	34359738367 kB
VmallocUsed	25000 kB
VmallocChunk	34359712763 kB
HugePages_Total	0
HugePages_Free	0
HugePages_Rsvd	0
HugePages_Surp	0
Hugepagesize	2048 kB
PCI Devices
PCI Devices
Host bridge	Silicon Integrated Systems [SiS] 755 Host
PCI bridge	Silicon Integrated Systems [SiS] SG86C202
ISA bridge	Silicon Integrated Systems [SiS] SiS964 [MuTIOL Media IO]
IDE interface	Silicon Integrated Systems [SiS] 5513 [IDE]
Multimedia audio controller	Silicon Integrated Systems [SiS] AC'97 Sound Controller
USB Controller	Silicon Integrated Systems [SiS] USB 1.1 Controller
USB Controller	Silicon Integrated Systems [SiS] USB 1.1 Controller
USB Controller	Silicon Integrated Systems [SiS] USB 1.1 Controller
USB Controller	Silicon Integrated Systems [SiS] USB 2.0 Controller
Ethernet controller	Silicon Integrated Systems [SiS] SiS900 PCI Fast Ethernet
Multimedia video controller	Conexant Systems, Inc. CX23880/1/2/3 PCI Video and Audio Decoder
FireWire (IEEE 1394)	VIA Technologies, Inc. VT6306 Fire II IEEE 1394 OHCI Link Layer Controller
Host bridge	Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] HyperTransport Technology Configuration
Host bridge	Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Address Map
Host bridge	Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] DRAM Controller
Host bridge	Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Miscellaneous Control
VGA compatible controller	ATI Technologies Inc RV280 [Radeon 9200 PRO]
Display controller	ATI Technologies Inc RV280 [Radeon 9200 PRO]
USB Devices
USB Devices
OHCI Host Controller	
OHCI Host Controller	
USB Camera	
USB Storage Device	
OHCI Host Controller	
Unknown USB 2,00 Device (class -591347264)	
EHCI Host Controller	

Sensors
ACPI Thermal Zone
THRM	17°C
Input Devices
Input Devices
Macintosh mouse button emulation	
AT Translated Set 2 keyboard	
HID 04b3:310b	
Power Button (FF)	
Power Button (CM)	
Sleep Button (CM)	
PC Speaker	
cx88 IR (Leadtek Winfast 2000XP	
Storage
IDE Disks
MAXTOR STM3160812A	
DVD-ROM BDV316E	
LITE-ON DVDRW SOHW-1633S	
SCSI Disks
IC USB Storage-CFC	
IC USB Storage-SMC	
IC USB Storage-MMC	
IC USB Storage-MSC	
DMI
BIOS
Date	09/02/2004
Vendor	Phoenix Technologies, LTD
Version	R03-A2
Board
Name	E31M
Vendor	Acer
Resources
I/O Ports
0000-001f 	dma1
0020-0021 	pic1
0040-0043 	timer0
0050-0053 	timer1
0060-0060 	keyboard
0064-0064 	keyboard
0070-0073 	rtc0
0080-008f 	dma page reg
00a0-00a1 	pic2
00c0-00df 	dma2
00f0-00ff 	fpu
0170-0177 	Silicon Integrated Systems [SiS] 5513 [IDE]
0170-0177 	SIS5513
01f0-01f7 	Silicon Integrated Systems [SiS] 5513 [IDE]
01f0-01f7 	SIS5513
0290-0297 	pnp 00:02
02f8-02ff 	serial
0376-0376 	Silicon Integrated Systems [SiS] 5513 [IDE]
0376-0376 	SIS5513
0378-037a 	parport0
03c0-03df 	vga+
03f2-03f5 	floppy
03f6-03f6 	Silicon Integrated Systems [SiS] 5513 [IDE]
03f6-03f6 	SIS5513
03f7-03f7 	floppy DIR
03f8-03ff 	serial
04d0-04d1 	pnp 00:02
0800-0805 	pnp 00:02
0cf8-0cff 	PCI conf1
1000-1003 	ACPI PM1a_EVT_BLK
1004-1005 	ACPI PM1a_CNT_BLK
1008-100b 	ACPI PM_TMR
1016-1016 	ACPI PM2_CNT_BLK
1020-1023 	ACPI GPE0_BLK
1030-1033 	ACPI GPE1_BLK
4000-400f 	Silicon Integrated Systems [SiS] 5513 [IDE]
4000-400f 	SIS5513
d000-dfff 	PCI Bus 0000:01
d000-d0ff 	ATI Technologies Inc RV280 [Radeon 9200 PRO]
e000-e0ff 	Silicon Integrated Systems [SiS] AC'97 Sound Controller
e000-e0ff 	SiS SI7012
e100-e17f 	Silicon Integrated Systems [SiS] AC'97 Sound Controller
e100-e17f 	SiS SI7012
e200-e2ff 	Silicon Integrated Systems [SiS] SiS900 PCI Fast Ethernet
e200-e2ff 	SiS 900 PCI Fast Ethernet driver
e300-e37f 	VIA Technologies, Inc. VT6306 Fire II IEEE 1394 OHCI Link Layer Controller
Memory
00000000-0009f7ff 	System RAM
0009f800-0009ffff 	reserved
000d0000-000d3fff 	pnp 00:00
000f0000-000fffff 	reserved
00100000-3ffeffff 	System RAM
00200000-0042cbea 	Kernel code
0042cbeb-0053b6f7 	Kernel data
005e0000-00675397 	Kernel bss
3fff0000-3fff2fff 	ACPI Non-volatile Storage
3fff3000-3fffffff 	ACPI Tables
50000000-5001ffff 	Silicon Integrated Systems [SiS] SiS900 PCI Fast Ethernet
a0000000-bfffffff 	GART
a0000000-bfffffff 	aperture
c0000000-cfffffff 	PCI Bus 0000:01
c0000000-c7ffffff 	ATI Technologies Inc RV280 [Radeon 9200 PRO]
c8000000-cfffffff 	ATI Technologies Inc RV280 [Radeon 9200 PRO]
d0000000-d0ffffff 	Conexant Systems, Inc. CX23880/1/2/3 PCI Video and Audio Decoder
d0000000-d0ffffff 	cx88[0]
d1000000-d10fffff 	PCI Bus 0000:01
d1000000-d101ffff 	ATI Technologies Inc RV280 [Radeon 9200 PRO]
d1020000-d102ffff 	ATI Technologies Inc RV280 [Radeon 9200 PRO]
d1030000-d103ffff 	ATI Technologies Inc RV280 [Radeon 9200 PRO]
d1120000-d1120fff 	Silicon Integrated Systems [SiS] USB 1.1 Controller
d1120000-d1120fff 	2006 August 04 USB 1.1 'Open' Host Controller (OHCI) Driver
d1121000-d1121fff 	Silicon Integrated Systems [SiS] USB 2.0 Controller
d1121000-d1121fff 	10 Dec 2004 USB 2.0 'Enhanced' Host Controller (EHCI) Driver
d1122000-d1122fff 	Silicon Integrated Systems [SiS] SiS900 PCI Fast Ethernet
d1122000-d1122fff 	SiS 900 PCI Fast Ethernet driver
d1123000-d1123fff 	Silicon Integrated Systems [SiS] USB 1.1 Controller
d1123000-d1123fff 	2006 August 04 USB 1.1 'Open' Host Controller (OHCI) Driver
d1124000-d1124fff 	Silicon Integrated Systems [SiS] USB 1.1 Controller
d1124000-d1124fff 	2006 August 04 USB 1.1 'Open' Host Controller (OHCI) Driver
d1125000-d11257ff 	VIA Technologies, Inc. VT6306 Fire II IEEE 1394 OHCI Link Layer Controller
d1125000-d11257ff 	Driver for PCI OHCI IEEE-1394 controllers
fec00000-fec00fff 	IOAPIC 0
fec00000-fec00fff 	reserved
fee00000-fee00fff 	Local APIC
fee00000-fee00fff 	reserved
ffee0000-ffefffff 	pnp 00:00
fffe0000-fffeffff 	pnp 00:00
ffff0000-ffffffff 	reserved
DMA
2	floppy
4	cascade