得到的时间发生不同的条目中的数据库查询的次数的计数(Android的) [英] Get a count of the number of times distinct entries occur in database query (Android)
问题描述
我有一个有点棘手的问题。我的应用程序输入用户数据到SQLite数据库和我已成功地编写查询来获取数据的退了出去。
I have a bit of a tricky problem. My app inputs user data into the SQLite database and I have managed to write queries to get the data back out.
这包括查询,获取不同值的列表中,例如可以如下。说你有以下数据:
This includes a query that gets a list of distinct values, an example may be as follows. Say you have the following data:
Column a | Column b | Column c
a a a
a b b
a b b
b b b
按组功能使用,查询将创建以下列表:
Using the 'group by' function, the query would create the following list:
aaa
abb
bbb
那么,我想,但没有做的是扩大这一点,让每个不同的项,则会出现次数的计数 - 因此,在上述情况下,它应该是这样的:
So what I am trying, but failing to do is expand this and get a count of the number of times each distinct entry occurs - so in the above case it would look like this:
1 x aaa
2 x abb
1 x bbb
那么,有没有一种方式,一旦你查询的数据库,让每个不同项的occurancies的计数,从光标 - 或者我需要写一个单独的查询来获得这些信息。
So is there a way, once you have queried the database, to get a count of the occurancies of each distinct entry, from the Cursor - or do I need to write a seperate query to get this information..
下面是我的查询,因为它看起来的时刻:
Here is my query as it looks at the moment:
public Cursor fetchDamagedComponentSpecForInspection(long inspectionId, String componentType) {
Cursor mCursor = rmDb.query(true, DAMAGED_COMPONENTS_TABLE, new String[] {
DAMAGED_COMPONENT_ID,
LOCATION_LINK,
RUN_LINK,
AREA_LINK,
INSPECTION_LINK,
LOCATION_REF,
RACKING_SYSTEM,
COMPONENT,
COMPONENT_TYPE,
QUANTITY,
POSITION,
RISK,
ACTION_REQUIRED,
NOTES_GENERAL,
MANUFACTURER,
TEXT1,
TEXT2,
TEXT3,
TEXT4,
NOTES_SPEC,
SPEC_SAVED},
INSPECTION_LINK + " = " + inspectionId + " AND " + COMPONENT_TYPE + " = ? AND " + SPEC_SAVED + " = ? ",
new String[] {componentType, "Yes"},
MANUFACTURER + ", " + TEXT1 + ", " + TEXT2 + ", " + TEXT3 + ", " + TEXT4 + ", " + NOTES_SPEC,
null, null, null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
有关更多的信息,这里是我的主要活动在这里我所说的查询和检索数据code:
For additional information, here is the code in my main activity where I call the query and retrieve the data:
final Cursor componentsAndSpecCursor = (Cursor) rmDbHelper.fetchComponentsAndSpecForManufacturer(inspectionId, rackingSystem, manufacturer);
if(componentsAndSpecCursor.moveToFirst()){
do {
componentType = componentsAndSpecCursor.getString(componentsAndSpecCursor.getColumnIndex(RMDbAdapter.COMPONENT_TYPE));
specText1 = componentsAndSpecCursor.getString(componentsAndSpecCursor.getColumnIndex(RMDbAdapter.TEXT1));
specText2 = componentsAndSpecCursor.getString(componentsAndSpecCursor.getColumnIndex(RMDbAdapter.TEXT2));
specText3 = componentsAndSpecCursor.getString(componentsAndSpecCursor.getColumnIndex(RMDbAdapter.TEXT3));
specText4 = componentsAndSpecCursor.getString(componentsAndSpecCursor.getColumnIndex(RMDbAdapter.TEXT4));
specNotes = componentsAndSpecCursor.getString(componentsAndSpecCursor.getColumnIndex(RMDbAdapter.NOTES_SPEC));
message.append(componentType).append(" ").append(specText1).append(" ").append(specText2).append(" ").append(specText3).append(" ").append(specText4).append(" ").append(specNotes).append("\r\n");
}
while (componentsAndSpecCursor.moveToNext());
}
componentsAndSpecCursor.close();
所以我也是不知道我将如何得到伯爵一旦我已包括在我的查询该位code的(我仍然无法看到它是怎么做的!)。
So I am also unaware of how I would get the Count once I have included this bit of code in my query (which I still can't see how it is done!).
推荐答案
这是你想要的查询是:
select count(*) as cnt, cola, colb, colc
from YourTable
group by cola, colb, colc
我不知道如何把这个到code。你似乎不有,在你提供的code的代码片段返回组合查询。
I'm not sure how to put this into your code. You don't seem to have a query that returns the combinations in the snippet of code that you provided.
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