Question

我的＆＃34; Android＆＃34;开发应用程序。

我试图从2个表中检索一些数据，例如：

post ( post_title, post_desc )

postmeta ( postmeta_value )

postmeta_ID是外键。我想从两个表中的帖子ID == 1中检索一些特定的（帖子标题，帖子desc和所有postmeta值）数据。

我已经使用了这种语法，但总是在SELECT＆＃34;：

附近说＆＃34;错误

String q2 = " SELECT  post_content, post_title, "
    + "land.postmeta_value landValue, "
    + "price.postmeta_value priceValue, "
    + "bedroom.postmeta_value bedroomValue, "
    + "bathroom.postmeta_value bathroomValue, "
    + "pool.postmeta_value poolValue,"
    + " type.postmeta_value typeValue, "
    + "ownership.postmeta_value ownershipValue, "
    + "location.postmeta_value locationValue, "
    + "poolType.postmeta_value poolTypeValue, "
    + "carPort.postmeta_value carPortValue, "
    + "so.postmeta_value soValue, "
    + "ct.postmeta_value ctValue "
    + "FROM post "
    + "INNER JOIN postmeta land ON post._id=land.postmeta_ID "
    + "INNER JOIN postmeta price ON post._id=price.postmeta_ID "
    + "INNER JOIN postmeta bedroom ON post._id=bedroom.postmeta_ID "
    + "INNER JOIN postmeta bathroom ON post._id=bathroom.postmeta_ID "
    + "INNER JOIN postmeta pool ON post._id=pool.postmeta_ID"
    + "INNER JOIN postmeta type ON post._id=type.postmeta_ID"
    + "INNER JOIN postmeta ownership ON post._id=ownership.postmeta_ID"
    + "INNER JOIN postmeta location ON post._id=location.postmeta_ID"
    + "INNER JOIN postmeta poolType ON post._id=poolType.postmeta_ID "
    + "INNER JOIN postmeta carPort ON post._id=carPort.postmeta_ID"
    + "INNER JOIN postmeta so ON post._id=so.postmeta_ID"
    + "INNER JOIN postmeta ct ON post._id=ct.postmeta_ID WHERE post_ID = 2";

当我只使用3个内连接时，它很好......但是当谈到这一点时，总是说错误。

我的语法有问题吗？或者在语法上使用内连接是否存在最大限制？

我无法附上表格结构截图，因为我没有10个声誉。

Answer 1

确保SQL字符串的每一行末尾都有空格，否则您最终会发送以下内容：

"INNER JOIN postmeta carPort ON post._id=carPort.postmeta_IDINNER JOIN postmeta so ON post._id=so.postmeta_ID"

到SQL解释器，它可能会吐出来。

Answer 2

没关系。我使用了这种语法：

SELECT post_title, post_content, postmeta_key, postmeta_value 
FROM post INNER JOIN postmeta land ON post._id=land.postmeta_ID 
WHERE postmeta_ID = " + postID + " AND postmeta_key IN ( 
    'landSize', 'buildingSize', 'propertyPrice', 'propertyBedroom', 
    'propertyBathroom', 'pool', 'propertyType', 'propertyOwnership', 
    'propertyLocation', 'propertyPoolType', 'propertyCarPort', 
    'propertySpecialOffer', 'propertyCurrencyType' 
)

从SQLITE中的同一字段中的多行检索数据

2 个答案: