如何根据参数使用不同的"where“子句？

String whereClause;
if (param.equals("value1")) {
    whereClause = "WHERE column1 = 'value1'";
} else if (param.equals("value2")) {
    whereClause = "WHERE column2 = 'value2'";
} else {
    whereClause = ""; // 默认情况下不添加"where"子句
}

String sql = "SELECT * FROM table " + whereClause;

where_clause = ""
if param == "value1":
    where_clause = "WHERE column1 = 'value1'"
elif param == "value2":
    where_clause = "WHERE column2 = 'value2'"

sql = "SELECT * FROM table " + where_clause

var query = dbContext.Table.AsQueryable();

if (param == "value1") {
    query = query.Where(t => t.Column1 == "value1");
} else if (param == "value2") {
    query = query.Where(t => t.Column2 == "value2");
}

var result = query.ToList();