use group by instead of distinct when possible

tools/dbutils/select.go

@@ -0,0 +1,18 @@
+package dbutils
+
+import "regexp"
+
+// Regexp for columns and tables (the same as the one in dbx).
+var selectRegex = regexp.MustCompile(`(?i:\s+as\s+|\s+)([\w\-_\.]+)$`)
+
+// AliasOrIdentifier returns the alias from a column or table identifier,
+// Returns the identifier unmodified if no alias was found.
+func AliasOrIdentifier(columnOrTableIdentifier string) string {
+	matches := selectRegex.FindStringSubmatch(columnOrTableIdentifier)
+
+	if len(matches) > 0 && matches[1] != "" {
+		return matches[1]
+	}
+
+	return columnOrTableIdentifier
+}