Add DECIMAL constructor for Float literal.

DECIMAL constructor is used to pass a decimal number to the SQL query without precision loss.

internal/jet/literal_expression.go

@@ -140,7 +140,7 @@ type floatLiteral struct {
 	literalExpressionImpl
 }
 
-// Float creates new float literal
+// Float creates new float literal from float64 value
 func Float(value float64) FloatExpression {
 	floatLiteral := floatLiteral{}
 	floatLiteral.literalExpressionImpl = *literal(value)
@@ -150,6 +150,16 @@ func Float(value float64) FloatExpression {
 	return &floatLiteral
 }
 
+// Decimal creates new float literal from string value
+func Decimal(value string) FloatExpression {
+	floatLiteral := floatLiteral{}
+	floatLiteral.literalExpressionImpl = *literal(value)
+
+	floatLiteral.floatInterfaceImpl.parent = &floatLiteral
+
+	return &floatLiteral
+}
+
 //---------------------------------------------------//
 type stringLiteral struct {
 	stringInterfaceImpl