Postgres：错误[42601]错误：在“$ 2”或其附近出现语法错误。错误而执行查询

Question

SELECT  
    to_char(messages. TIME, 'YYYY/MM/DD') AS FullDate, 
    to_char(messages. TIME, 'MM/DD') AS PartialDate, 
      COUNT(CASE WHEN message_definitions.error_category = ? THEN 1 END) AS Errors, 
    error_categories.threshold, 
    COUNT(CASE WHEN messages.message_id = 14 THEN 1 END) AS Picks 
FROM  
    messages LEFT JOIN 
    message_definitions USING (message_id) LEFT JOIN 
    error_categories USING (error_category) 
WHERE 
    (messages. TIME > TIMESTAMP ? - '30 day'::INTERVAL) AND 
    (messages. TIME < TIMESTAMP '2016-08-03' + '1 day'::INTERVAL) AND 
    (messages.system_id = ?) AND 
    (messages.message_id = 14 OR 
    message_definitions.error_category = ?) 
GROUP BY 
    FullDate, PartialDate, error_categories.threshold 
ORDER BY 
    FullDate DESC LIMIT 40 

在上面的查询，在where子句，（第一行：。？（消息TIME>时间戳 - '30天'::间隔） ）当参数类型强制转换（即当我把之前TIMESTAMP？）我收到以下错误

这是不是在第二行文本数据真实（消息。TIME < TIMESTAMP“2016年8月3日” +“ 1天':: INTERVAL）和

当我将该子句更改为（消息。 TIME>？ :: TIMESTAMP - '30 day':: INTERVAL）和 ） （即我把TIMESTAMP放在？之后？） 任何人都可以对发生的事情有所了解吗？谢谢！！

注： PostGresVersion - 9.6 ODBC驱动程序 - 32位驱动程序（位于C：\ Program Files文件（x86）的\ psqlODBC \ 0905 \ BIN \ psqlodbc30a.dll） 同样是Postgres的8.4也是如此。

Answer 1

The documentation说：

A constant of an arbitrary type can be entered using any one of the following notations:

type 'string'
'string'::type
CAST ('string' AS type)

The string constant's text is passed to the input conversion routine for the type called type. The result is a constant of the indicated type.

[...]

The :: , CAST() , and function-call syntaxes can also be used to specify run-time type conversions of arbitrary expressions, as discussed in Section 4.2.9. To avoid syntactic ambiguity, the type 'string' syntax can only be used to specify the type of a simple literal constant.

所以，你可以为你正在尝试做使用此语法仅用于字符串，而不是用一个参数。