Initial Databricks SQL dialect (#1220)

tests/sqlparser_databricks.rs

@@ -0,0 +1,30 @@
+use sqlparser::ast::*;
+use sqlparser::dialect::DatabricksDialect;
+use test_utils::*;
+
+#[macro_use]
+mod test_utils;
+
+fn databricks() -> TestedDialects {
+    TestedDialects {
+        dialects: vec![Box::new(DatabricksDialect {})],
+        options: None,
+    }
+}
+
+#[test]
+fn test_databricks_identifiers() {
+    // databricks uses backtick for delimited identifiers
+    assert_eq!(
+        databricks().verified_only_select("SELECT `Ä`").projection[0],
+        SelectItem::UnnamedExpr(Expr::Identifier(Ident::with_quote('`', "Ä")))
+    );
+
+    // double quotes produce string literals, not delimited identifiers
+    assert_eq!(
+        databricks()
+            .verified_only_select(r#"SELECT "Ä""#)
+            .projection[0],
+        SelectItem::UnnamedExpr(Expr::Value(Value::DoubleQuotedString("Ä".to_owned())))
+    );
+}