When using the LogMode(true), the SQL produced during the log message, places the bounded variables in the wrong location, this is due to the fact that the current implementation splits the values with a regex similar to: ($\d+)|?.

That works well for ? placeholders because they should be replaced in order.

However, the numeric placeholders should be replaced based on their value, for instance:

SELECT name,last FROM contact WHERE name=$2 and age=$1
Should NOT be replaced in order, because it will yield an incorrectly formed SQL command, which is not very useful for debugging.

Fixes issue: #1249

logger.go

@@ -12,8 +12,9 @@ import (
 )
 
 var (
-	defaultLogger = Logger{log.New(os.Stdout, "\r\n", 0)}
-	sqlRegexp     = regexp.MustCompile(`(\$\d+)|\?`)
+	defaultLogger            = Logger{log.New(os.Stdout, "\r\n", 0)}
+	sqlRegexp                = regexp.MustCompile(`\?`)
+	numericPlaceHolderRegexp = regexp.MustCompile(`\$\d+`)
 )
 
 type logger interface {
@@ -71,11 +72,21 @@ func (logger Logger) Print(values ...interface{}) {
 				}
 			}
 
-			var formattedValuesLength = len(formattedValues)
-			for index, value := range sqlRegexp.Split(values[3].(string), -1) {
-				sql += value
-				if index < formattedValuesLength {
-					sql += formattedValues[index]
+			// differentiate between $n placeholders or else treat like ?
+			if numericPlaceHolderRegexp.MatchString(values[3].(string)) {
+				sql = values[3].(string)
+				for index, value := range formattedValues {
+					placeholder := fmt.Sprintf(`\$%d`, index+1)
+					subre := regexp.MustCompile(placeholder)
+					sql = subre.ReplaceAllString(sql, value)
+				}
+			} else {
+				var formattedValuesLength = len(formattedValues)
+				for index, value := range sqlRegexp.Split(values[3].(string), -1) {
+					sql += value
+					if index < formattedValuesLength {
+						sql += formattedValues[index]
+					}
 				}
 			}