BETWEEN Support

Author: gilsonjoanelo

src/FirebirdSql.EntityFrameworkCore.Firebird/Query/Internal/FbQuerySqlGenerator.cs

@@ -143,17 +143,23 @@ protected override Expression VisitSqlBinary(SqlBinaryExpression sqlBinaryExpres
 			Sql.Append(")");
 			return sqlBinaryExpression;
 		}
-		else
+		else if (sqlBinaryExpression.OperatorType == ExpressionType.AndAlso)
 		{
-			return base.VisitSqlBinary(sqlBinaryExpression);
-		}
-
-		void BooleanToIntegralAndVisit(SqlExpression expression)
-		{
-			Sql.Append("IIF(");
-			Visit(expression);
-			Sql.Append(", 1, 0)");
+			if (sqlBinaryExpression.Left is SqlBinaryExpression left &&
+				sqlBinaryExpression.Right is SqlBinaryExpression right &&
+				left.OperatorType == ExpressionType.GreaterThanOrEqual &&
+				right.OperatorType == ExpressionType.LessThanOrEqual &&
+				left.Left.Equals(right.Left))
+			{
+				Visit(left.Left);
+				Sql.Append(" BETWEEN ");
+				Visit(left.Right);
+				Sql.Append(" AND ");
+				Visit(right.Right);
+				return sqlBinaryExpression;
+			}
 		}
+		return base.VisitSqlBinary(sqlBinaryExpression);
 	}
 
 	protected override Expression VisitSqlParameter(SqlParameterExpression sqlParameterExpression)
@@ -413,4 +419,11 @@ void GenerateList<T>(IReadOnlyList<T> items, Action<T> generationAction, Action<
 			generationAction(items[i]);
 		}
 	}
+
+	void BooleanToIntegralAndVisit(SqlExpression expression)
+	{
+		Sql.Append("IIF(");
+		Visit(expression);
+		Sql.Append(", 1, 0)");
+	}
 }