Question

lvalue required as left operand of assignment

上面的python / psycopg2代码给出了以下错误：

query = """UPDATE table SET last_tracked = %s, being_tracked = %s WHERE(
                SELECT 'X' FROM temp_table
                WHERE table.selected_id = temp_table.selected_id);"""
cur.execute(query, [datetime.utcnow().isoformat(' ').split('.')[0] + ' z', True])

以下代码完美无缺：

ERROR:  failed to find conversion function from unknown to boolean
STATEMENT:  UPDATE table 
            SET last_tracked = '2015-07-02 20:32:00 z', being_tracked = true 
            WHERE(
                SELECT 'X' FROM temp_table
                WHERE table.selected_id = temp_table.selected_id);

我尝试仅更新表中已存在的行。我在这里做错了什么？

Answer 1

你错过了WHERE谓词中的EXISTS：

query =“”“UPDATE表SET last_tracked =％s，being_tracked =％s WHERE（从temp_table中选择“X” table.selected_id = temp_table.selected_id）;“”“

应该是：

query =“”“UPDATE表SET last_tracked =％s，being_tracked =％s WHERE EXISTS（从temp_table中选择“X” table.selected_id = temp_table.selected_id）;“”“

不要？

无法找到从未知到布尔错误的转换函数

1 个答案: