Improve the SQL strings concat rules to handle multiple string concatenation

Signed-off-by: Cosmin Cojocar <cosmin.cojocar@gmx.ch>

helpers.go

@@ -226,6 +226,27 @@ func GetIdentStringValues(ident *ast.Ident) []string {
 	return values
 }
 
+// GetBinaryExprOperands returns all operands of a binary expression by traversing
+// the expression tree
+func GetBinaryExprOperands(be *ast.BinaryExpr) []ast.Node {
+	var traverse func(be *ast.BinaryExpr)
+	result := []ast.Node{}
+	traverse = func(be *ast.BinaryExpr) {
+		if lhs, ok := be.X.(*ast.BinaryExpr); ok {
+			traverse(lhs)
+		} else {
+			result = append(result, be.X)
+		}
+		if rhs, ok := be.Y.(*ast.BinaryExpr); ok {
+			traverse(rhs)
+		} else {
+			result = append(result, be.Y)
+		}
+	}
+	traverse(be)
+	return result
+}
+
 // GetImportedName returns the name used for the package within the
 // code. It will resolve aliases and ignores initialization only imports.
 func GetImportedName(path string, ctx *Context) (string, bool) {