Updated docs

Author: kiraksi

README.rst

@@ -36,7 +36,7 @@ In order to use this library, you first need to go through the following steps:
 
 .. note::
    This library is a prerelease to gauge compatiblity with SQLAlchemy
-   versions >= 2.0.0
+   versions >= 1.4.16 < 2.1
 
 Installation
 ------------

sqlalchemy_bigquery/test.py

@@ -0,0 +1,6 @@
+from sqlalchemy.sql.expression import cast
+from sqlalchemy import String, func
+code_coding = db.query(func.unnest(self.model.code_coding)).subquery()
+conditions.append(
+    and_(cast(code_coding.c.code, String) == "H", cast(code_coding.c.display, String) == "BLAST")
+)