diff --git a/htdocs/accountancy/admin/card.php b/htdocs/accountancy/admin/card.php
index cd48526e62b..4d69eae7db8 100644
--- a/htdocs/accountancy/admin/card.php
+++ b/htdocs/accountancy/admin/card.php
@@ -75,7 +75,7 @@ if ($action == 'add' && $user->rights->accounting->chartofaccount) {
 			setEventMessages($langs->trans("ErrorFieldRequired", $langs->transnoentities("Label")), null, 'errors');
 			$action = 'create';
 		} else {
-			$sql = 'SELECT pcg_version FROM ' . MAIN_DB_PREFIX . 'accounting_system WHERE rowid='.((int) $conf->global->CHARTOFACCOUNTS);
+			$sql = "SELECT pcg_version FROM " . MAIN_DB_PREFIX . "accounting_system WHERE rowid = ".((int) $conf->global->CHARTOFACCOUNTS);
 
 			dol_syslog('accountancy/admin/card.php:: $sql=' . $sql);
 			$result = $db->query($sql);
@@ -138,7 +138,7 @@ if ($action == 'add' && $user->rights->accounting->chartofaccount) {
 		} else {
 			$result = $object->fetch($id);
 
-			$sql = 'SELECT pcg_version FROM '.MAIN_DB_PREFIX.'accounting_system WHERE rowid='.((int) $conf->global->CHARTOFACCOUNTS);
+			$sql = "SELECT pcg_version FROM ".MAIN_DB_PREFIX."accounting_system WHERE rowid=".((int) $conf->global->CHARTOFACCOUNTS);
 
 			dol_syslog('accountancy/admin/card.php:: $sql=' . $sql);
 			$result2 = $db->query($sql);
@@ -260,7 +260,7 @@ if ($action == 'create') {
 	print '<input type="text" name="pcg_type" list="pcg_type_datalist" value="'.dol_escape_htmltag(GETPOSTISSET('pcg_type') ? GETPOST('pcg_type', 'alpha') : $object->pcg_type).'">';
 	// autosuggest from existing account types if found
 	print '<datalist id="pcg_type_datalist">';
-	$sql = 'SELECT DISTINCT pcg_type FROM ' . MAIN_DB_PREFIX . 'accounting_account';
+	$sql = "SELECT DISTINCT pcg_type FROM " . MAIN_DB_PREFIX . "accounting_account";
 	$sql .= " WHERE fk_pcg_version = '" . $db->escape($accountsystem->ref) . "'";
 	$sql .= ' AND entity in ('.getEntity('accounting_account', 0).')';		// Always limit to current entity. No sharing in accountancy.
 	$sql .= ' LIMIT 50000'; // just as a sanity check
diff --git a/htdocs/accountancy/journal/bankjournal.php b/htdocs/accountancy/journal/bankjournal.php
index d05135e7a67..4367241dbd7 100644
--- a/htdocs/accountancy/journal/bankjournal.php
+++ b/htdocs/accountancy/journal/bankjournal.php
@@ -362,7 +362,7 @@ if ($result) {
 
 					// Retrieve the accounting code of the social contribution of the payment from link of payment.
 					// Note: We have the social contribution id, it can be faster to get accounting code from social contribution id.
-					$sqlmid = 'SELECT cchgsoc.accountancy_code';
+					$sqlmid = "SELECT cchgsoc.accountancy_code";
 					$sqlmid .= " FROM ".MAIN_DB_PREFIX."c_chargesociales cchgsoc";
 					$sqlmid .= " INNER JOIN ".MAIN_DB_PREFIX."chargesociales as chgsoc ON chgsoc.fk_type = cchgsoc.id";
 					$sqlmid .= " INNER JOIN ".MAIN_DB_PREFIX."paiementcharge as paycharg ON paycharg.fk_charge = chgsoc.rowid";
@@ -1019,7 +1019,7 @@ if (empty($action) || $action == 'view') {
 
 
 	// Test that setup is complete (we are in accounting, so test on entity is always on $conf->entity only, no sharing allowed)
-	$sql = 'SELECT COUNT(rowid) as nb FROM '.MAIN_DB_PREFIX.'bank_account WHERE entity = '.$conf->entity.' AND fk_accountancy_journal IS NULL AND clos=0';
+	$sql = "SELECT COUNT(rowid) as nb FROM ".MAIN_DB_PREFIX."bank_account WHERE entity = ".((int) $conf->entity)." AND fk_accountancy_journal IS NULL AND clos=0";
 	$resql = $db->query($sql);
 	if ($resql) {
 		$obj = $db->fetch_object($resql);
diff --git a/htdocs/admin/multicurrency.php b/htdocs/admin/multicurrency.php
index 95b418a75f0..e8619219471 100644
--- a/htdocs/admin/multicurrency.php
+++ b/htdocs/admin/multicurrency.php
@@ -138,7 +138,7 @@ if ($action == 'add_currency') {
 
 
 $TCurrency = array();
-$sql = 'SELECT rowid FROM '.MAIN_DB_PREFIX.'multicurrency WHERE entity = '.$conf->entity;
+$sql = "SELECT rowid FROM ".MAIN_DB_PREFIX."multicurrency WHERE entity = ".((int) $conf->entity);
 $resql = $db->query($sql);
 if ($resql) {
 	while ($obj = $db->fetch_object($resql)) {
diff --git a/htdocs/compta/paiement/class/paiement.class.php b/htdocs/compta/paiement/class/paiement.class.php
index 3e1dc59a52e..aab54e4ef81 100644
--- a/htdocs/compta/paiement/class/paiement.class.php
+++ b/htdocs/compta/paiement/class/paiement.class.php
@@ -304,8 +304,8 @@ class Paiement extends CommonObject
 				$facid = $key;
 				if (is_numeric($amount) && $amount <> 0) {
 					$amount = price2num($amount);
-					$sql = 'INSERT INTO '.MAIN_DB_PREFIX.'paiement_facture (fk_facture, fk_paiement, amount, multicurrency_amount)';
-					$sql .= ' VALUES ('.((int) $facid).', '.((int) $this->id).", ".((float) $amount).", ".((float) $this->multicurrency_amounts[$key]).')';
+					$sql = "INSERT INTO ".MAIN_DB_PREFIX."paiement_facture (fk_facture, fk_paiement, amount, multicurrency_amount)";
+					$sql .= " VALUES (".((int) $facid).", ".((int) $this->id).", ".((float) $amount).", ".((float) $this->multicurrency_amounts[$key]).")";
 
 					dol_syslog(get_class($this).'::create Amount line '.$key.' insert paiement_facture', LOG_DEBUG);
 					$resql = $this->db->query($sql);
diff --git a/htdocs/core/class/commoninvoice.class.php b/htdocs/core/class/commoninvoice.class.php
index dfabfd24ebe..9bd17c77ea5 100644
--- a/htdocs/core/class/commoninvoice.class.php
+++ b/htdocs/core/class/commoninvoice.class.php
@@ -734,7 +734,7 @@ abstract class CommonInvoice extends CommonObject
 							$sql .= 'fk_facture, ';
 						}
 						$sql .= ' amount, date_demande, fk_user_demande, code_banque, code_guichet, number, cle_rib, sourcetype, entity)';
-						$sql .= ' VALUES ('.((int) $this->id);
+						$sql .= " VALUES (".((int) $this->id);
 						$sql .= ", ".((float) price2num($amount));
 						$sql .= ", '".$this->db->idate($now)."'";
 						$sql .= ", ".((int) $fuser->id);
diff --git a/htdocs/core/class/commonobject.class.php b/htdocs/core/class/commonobject.class.php
index 3c95d9c26a0..ca3cc7ad39d 100644
--- a/htdocs/core/class/commonobject.class.php
+++ b/htdocs/core/class/commonobject.class.php
@@ -8682,7 +8682,7 @@ abstract class CommonObject
 			// If field is an implicit foreign key field
 			if (preg_match('/^integer:/i', $this->fields[$key]['type']) && empty($values[$key])) {
 				if (isset($this->fields[$key]['default'])) {
-					$values[$key] = $this->fields[$key]['default'];
+					$values[$key] = ((int) $this->fields[$key]['default']);
 				} else {
 					$values[$key] = 'null';
 				}
@@ -8699,9 +8699,9 @@ abstract class CommonObject
 		$this->db->begin();
 
 		if (!$error) {
-			$sql = 'INSERT INTO '.MAIN_DB_PREFIX.$this->table_element;
-			$sql .= ' ('.implode(", ", $keys).')';
-			$sql .= ' VALUES ('.implode(", ", $values).')';
+			$sql = "INSERT INTO ".MAIN_DB_PREFIX.$this->table_element;
+			$sql .= " (".implode(", ", $keys).')';
+			$sql .= " VALUES (".implode(", ", $values).")";		// $values can contains 'abc' or 123
 
 			$res = $this->db->query($sql);
 			if ($res === false) {
@@ -8717,7 +8717,7 @@ abstract class CommonObject
 		// If we have a field ref with a default value of (PROV)
 		if (!$error) {
 			if (key_exists('ref', $this->fields) && $this->fields['ref']['notnull'] > 0 && key_exists('default', $this->fields['ref']) && $this->fields['ref']['default'] == '(PROV)') {
-				$sql = "UPDATE ".MAIN_DB_PREFIX.$this->table_element." SET ref = '(PROV".$this->id.")' WHERE (ref = '(PROV)' OR ref = '') AND rowid = ".((int) $this->id);
+				$sql = "UPDATE ".MAIN_DB_PREFIX.$this->table_element." SET ref = '(PROV".((int) $this->id).")' WHERE (ref = '(PROV)' OR ref = '') AND rowid = ".((int) $this->id);
 				$resqlupdate = $this->db->query($sql);
 
 				if ($resqlupdate === false) {
diff --git a/htdocs/webservices/server_supplier_invoice.php b/htdocs/webservices/server_supplier_invoice.php
index 6803133d527..926fa8f6418 100644
--- a/htdocs/webservices/server_supplier_invoice.php
+++ b/htdocs/webservices/server_supplier_invoice.php
@@ -350,13 +350,9 @@ function getSupplierInvoicesForThirdParty($authentication, $idthirdparty)
 	if (!$error) {
 		$linesinvoice = array();
 
-		$sql .= 'SELECT f.rowid as facid';
-		$sql .= ' FROM '.MAIN_DB_PREFIX.'facture_fourn as f';
-		//$sql.=', '.MAIN_DB_PREFIX.'societe as s';
-		//$sql.= ' LEFT JOIN '.MAIN_DB_PREFIX.'product as p ON pt.fk_product = p.rowid';
-		//$sql.=" WHERE f.fk_soc = s.rowid AND nom = '".$db->escape($idthirdparty)."'";
-		//$sql.=" WHERE f.fk_soc = s.rowid AND nom = '".$db->escape($idthirdparty)."'";
-		$sql .= " WHERE f.entity = ".$conf->entity;
+		$sql .= "SELECT f.rowid as facid";
+		$sql .= " FROM '.MAIN_DB_PREFIX.'facture_fourn as f";
+		$sql .= " WHERE f.entity = ".((int) $conf->entity);
 		if ($idthirdparty != 'all') {
 			$sql .= " AND f.fk_soc = ".((int) $idthirdparty);
 		}
diff --git a/test/phpunit/CodingPhpTest.php b/test/phpunit/CodingPhpTest.php
index 21a58f34159..414daa21632 100644
--- a/test/phpunit/CodingPhpTest.php
+++ b/test/phpunit/CodingPhpTest.php
@@ -250,7 +250,6 @@ class CodingPhpTest extends PHPUnit\Framework\TestCase
 
 			$ok=true;
 			$matches=array();
-			// Check string get_class...
 			preg_match_all('/'.preg_quote('get_class($this)."::".__METHOD__', '/').'/', $filecontent, $matches, PREG_SET_ORDER);
 			foreach ($matches as $key => $val) {
 				$ok=false;
@@ -260,9 +259,9 @@ class CodingPhpTest extends PHPUnit\Framework\TestCase
 			$this->assertTrue($ok, 'Found string get_class($this)."::".__METHOD__ that must be replaced with __METHOD__ only in '.$file['relativename']);
 			//exit;
 
+			// Check string $this->db->idate without quotes
 			$ok=true;
 			$matches=array();
-			// Check string $this->db->idate without quotes
 			preg_match_all('/(..)\s*\.\s*\$this->db->idate\(/', $filecontent, $matches, PREG_SET_ORDER);
 			foreach ($matches as $key => $val) {
 				if ($val[1] != '\'"' && $val[1] != '\'\'') {
@@ -276,11 +275,10 @@ class CodingPhpTest extends PHPUnit\Framework\TestCase
 			//exit;
 
 
-			$ok=true;
-			$matches=array();
-
 			// Check sql string DELETE|OR|AND|WHERE|INSERT ... yyy = ".$xxx
 			//  with xxx that is not 'thi' (for $this->db->sanitize) and 'db-' (for $db->sanitize). It means we forget a ' if string, or an (int) if int, when forging sql request.
+			$ok=true;
+			$matches=array();
 			preg_match_all('/(DELETE|OR|AND|WHERE|INSERT)\s.*([^\s][^\s][^\s])\s*=\s*"\s*\.\s*\$(...)/', $filecontent, $matches, PREG_SET_ORDER);
 			foreach ($matches as $key => $val) {
 				if ($val[2] == 'ity' && $val[3] == 'con') {		// exclude entity = ".$conf->entity
@@ -300,8 +298,39 @@ class CodingPhpTest extends PHPUnit\Framework\TestCase
 			$this->assertTrue($ok, 'Found non quoted or not casted var into sql request '.$file['relativename'].' - Bad.');
 			//exit;
 
+			// Check that forged sql string is using " as string PHP quotes
+			$ok=true;
+			$matches=array();
+			preg_match_all('/\$sql \.= \'\s*VALUES.*\$/', $filecontent, $matches, PREG_SET_ORDER);
+			foreach ($matches as $key => $val) {
+				//if ($val[1] != '\'"' && $val[1] != '\'\'') {
+					var_dump($matches);
+					$ok=false;
+					break;
+				//}
+				//if ($reg[0] != 'db') $ok=false;
+			}
+			//print __METHOD__." Result for checking we don't have non escaped string in sql requests for file ".$file."\n";
+			$this->assertTrue($ok, 'Found a forged SQL string that mix on same line the use of \' for PHP string and PHP variables into file '.$file['relativename'].' Use " to forge PHP string like this: $sql = "SELET ".$myvar...');
+			//exit;
+
+			// Check that forged sql string is using " as string PHP quotes
+			/*
+			$ok=true;
+			$matches=array();
+			preg_match_all('/\$sql \.*= \'SELECT.*\$/', $filecontent, $matches, PREG_SET_ORDER);
+			foreach ($matches as $key => $val) {
+				var_dump($matches);
+				$ok=false;
+				break;
+			}
+			$this->assertTrue($ok, 'Found a forged SQL string that mix on same line the use of \' for PHP string and PHP variables into file '.$file['relativename'].' Use " to forge PHP string like this: $sql = "SELET ".$myvar...');
+			*/
+
 			// Check sql string VALUES ... , ".$xxx
 			//  with xxx that is not 'db-' (for $db->escape). It means we forget a ' if string, or an (int) if int, when forging sql request.
+			$ok=true;
+			$matches=array();
 			preg_match_all('/(VALUES).*,\s*"\s*\.\s*\$(...)/', $filecontent, $matches, PREG_SET_ORDER);
 			foreach ($matches as $key => $val) {
 				if ($val[1] == 'VALUES' && $val[2] == 'db-') {		// exclude $db->escape(
@@ -321,6 +350,8 @@ class CodingPhpTest extends PHPUnit\Framework\TestCase
 			// Check '".$xxx non escaped
 
 			// Check string   ='".$this->xxx   with xxx that is not 'escape'. It means we forget a db->escape when forging sql request.
+			$ok=true;
+			$matches=array();
 			preg_match_all('/=\s*\'"\s*\.\s*\$this->(....)/', $filecontent, $matches, PREG_SET_ORDER);
 			foreach ($matches as $key => $val) {
 				if ($val[1] != 'db->' && $val[1] != 'esca') {
@@ -332,6 +363,8 @@ class CodingPhpTest extends PHPUnit\Framework\TestCase
 			$this->assertTrue($ok, 'Found non escaped string in building of a sql request (case 1) in '.$file['relativename'].' - Bad.');
 
 			// Check string sql|set...'".$yyy->xxx   with xxx that is not 'escape', 'idate', .... It means we forget a db->escape when forging sql request.
+			$ok=true;
+			$matches=array();
 			preg_match_all('/(sql|SET|WHERE|INSERT|VALUES).+\s*\'"\s*\.\s*\$(.........)/', $filecontent, $matches, PREG_SET_ORDER);
 			foreach ($matches as $key => $val) {
 				if (! in_array($val[2], array('this->db-', 'this->esc', 'db->escap', 'dbs->esca', 'mydb->esc', 'dbsession', 'db->idate', 'escapedli', 'excludeGr', 'includeGr'))) {
@@ -345,6 +378,8 @@ class CodingPhpTest extends PHPUnit\Framework\TestCase
 			//exit;
 
 			// Check string sql|set...'.$yyy->xxx   with xxx that is not 'escape', 'idate', .... It means we forget a db->escape when forging sql request.
+			$ok=true;
+			$matches=array();
 			preg_match_all('/(\$sql|SET\s|WHERE\s|INSERT\s|VALUES\s|VALUES\().+\s*\'\s*\.\s*\$(.........)/', $filecontent, $matches, PREG_SET_ORDER);
 			foreach ($matches as $key => $val) {
 				if (! in_array($val[2], array('this->db-', 'db->sanit', 'conf->ent', 'key : \'\')', 'key])."\')', 'excludefi', 'regexstri', ''))) {
@@ -361,6 +396,8 @@ class CodingPhpTest extends PHPUnit\Framework\TestCase
 			// Checks with IN
 
 			// Check string 'IN (".xxx' or 'IN (\'.xxx'  with xxx that is not '$this->db->sanitize' and not '$db->sanitize'. It means we forget a db->sanitize when forging sql request.
+			$ok=true;
+			$matches=array();
 			preg_match_all('/ IN \([\'"]\s*\.\s*(.........)/i', $filecontent, $matches, PREG_SET_ORDER);
 			foreach ($matches as $key => $val) {
 				if (!in_array($val[1], array('$db->sani', '$this->db', 'getEntity', 'WON\',\'L', 'self::STA', 'Commande:', 'CommandeF', 'Entrepot:', 'Facture::', 'FactureFo', 'ExpenseRe', 'Societe::', 'Ticket::S'))) {
@@ -374,6 +411,8 @@ class CodingPhpTest extends PHPUnit\Framework\TestCase
 			//exit;
 
 			// Check string 'IN (\'".xxx'   with xxx that is not '$this->db->sanitize' and not '$db->sanitize'. It means we forget a db->sanitize when forging sql request.
+			$ok=true;
+			$matches=array();
 			preg_match_all('/ IN \(\'"\s*\.\s*(.........)/i', $filecontent, $matches, PREG_SET_ORDER);
 			foreach ($matches as $key => $val) {
 				if (!in_array($val[1], array('$db->sani', '$this->db', 'getEntity', 'WON\',\'L', 'self::STA', 'Commande:', 'CommandeF', 'Entrepot:', 'Facture::', 'FactureFo', 'ExpenseRe', 'Societe::', 'Ticket::S'))) {