Develop Reference

How to make... SQLite select DISTINCT -> query(true, ...)

My query is:
String _query = "select DISTINCT Y.CATE_CODE4 CATE_CODE, Y.CATE_NAME4 CATE_NAME,
0 IS_PRESET from G_MASTER X INNER JOIN CATEGORY_VIEW Y ON X.CATE_4 = Y.CATE_CODE4
where X.IS_SALE = 1 AND Y.IS_LOCKED4 = 0 AND Y.CATE_NAME2 not in ('XXXX')";
How does Android SQLite make db.query()?

First of all you should read SQLiteDatabase reference.
You could use a rawQuery(), here's an example of it :
rawQuery - db.rawQuery("select DISTINCT Y.CATE_CODE4 CATE_CODE, Y.CATE_NAME4 CATE_NAME,
0 IS_PRESETG_MASTER X INNER JOIN CATEGORY_VIEW Y ON X.CATE_4 = Y.CATE_CODE4 from table where X.IS_SALE = 1 AND Y.IS_LOCKED4 = 0 AND Y.CATE_NAME2 not in ('XXXX')"",new String[]{"data"});
It's just an example, you have to adapt your code to this.

No such a column: R1.ReadingDate Error

I have created a view in sqlite using sqlite manager.
Create View vMeterReading
as
SELECT M._id as Meter_id, M.MeterNumber, R1.ReadingDate, R1.Reading AS CurrentReading, R2.ReadingDate AS PrevReadingDate, R2.Reading AS PrevMeterReading, R2.Rate as Rate, R2._id,R1.TenantMeter_id
FROM (Meters AS M INNER JOIN TenantMeters ON M._id = TenantMeters.Meter_id) INNER JOIN (MeterReading AS R1 INNER JOIN MeterReading AS R2 ON R1.TenantMeter_id = R2.TenantMeter_id) ON TenantMeters._id = R1.TenantMeter_id
WHERE (((R2.ReadingDate)=(SELECT Max(R3.ReadingDate)
FROM [MeterReading] AS R3
WHERE (R3.TenantMeter_id = R1.TenantMeter_id)
AND (R3.ReadingDate < R1.ReadingDate)
))) OR (((R2.TenantMeter_id) Is Null))
ORDER BY M.MeterNumber, R1.ReadingDate.
I have tried to use this view (select * from vMeterReading) in android and I get the error as titled.
I have also connected to the sqlite db from command prompt and tried to execute the same query. I get the same error.
What is wrong with the sql statement?
It works well in sql manager(firefox add-on).

SQLite makes no guarantees whether a table name prefix (like R1.1) is part of the result column name, or not.
You should explicitly give a name to all the view's columns with AS.

The problem was that the SQLite version used by android is not the same as the version used by sQLite manager. The android version does not support the join i was using.
The query below executes with out problems.
Got this advice from this site http://sqlite.1065341.n5.nabble.com/
SELECT M._id as Meter_id, M.MeterNumber, R1.ReadingDate as ReadingDate,
R1.Reading AS CurrentReading, R2.ReadingDate AS PrevReadingDate, R2.Reading
AS PrevMeterReading, R2.Rate as Rate, R2._id as _id,R1.TenantMeter_id as TenantMeterID
FROM Meters AS M INNER JOIN TenantMeters ON M._id = TenantMeters.Meter_id
INNER JOIN MeterReading AS R1 ON R1.TenantMeter_id = TenantMeters ._id
INNER JOIN MeterReading AS R2 ON
R1.TenantMeter_id = R2.TenantMeter_id
WHERE (((R2.ReadingDate)=(SELECT Max(R3.ReadingDate)
FROM [MeterReading] AS R3
WHERE (R3.TenantMeter_id = R1.TenantMeter_id)
AND (R3.ReadingDate < R1.ReadingDate)
))) OR (((R2.TenantMeter_id) Is Null))

how to add double quotation around variable name in query ?

How do I add quotation around string variable any idea? my database execute query if "" is around variable name what do I do ? I did this"+"+ School_name+"+"but its not working how I add variable name with quotation ?
Bundle bundle = this.getIntent().getExtras();
School_name = bundle.getString("Serachvalue");
db.selectQuery("SELECT * FROM uss_school sch LEFT JOIN uss_school_to_level sl ON
sch.school_id = sl.school_id LEFT JOIN uss_level l ON sl.level_id = l.level_id WHERE
l.title ="+ School_name+" ORDER BY sch.name ASC");
But data base execute wuery with in quotes,
SELECT * FROM uss_school sch LEFT JOIN uss_school_to_level sl ON sch.school_id =
sl.school_id LEFT JOIN uss_level l ON sl.level_id
= l.level_id WHERE l.title = "Elementary" ORDER BY sch.name ASC

Try following way,
db.selectQuery("SELECT * FROM uss_school sch LEFT JOIN uss_school_to_level sl ON
sch.school_id = sl.school_id LEFT JOIN uss_level l ON sl.level_id = l.level_id WHERE
l.title ='"+ School_name+"' ORDER BY sch.name ASC");
You simply need to add ' whenever you are using string variable in query field.

How to insert a table in to group in Corona SDK (.Lua)?

I get error message when i try to insert a table into a group
My table code is containing images
Here is the code i am using for the table
local myJoints = {}
for i = 1,5 do
local link = {}
for j = 1,17 do
link[j] = display.newImage( "link.png" )
link[j].x = 121 + (i*34)
link[j].y = 55 + (j*17)
physics.addBody( link[j], { density=2.0, friction=0, bounce=0 } )
-- Create joints between links
if (j > 1) then
prevLink = link[j-1] -- each link is joined with the one above it
else
prevLink = wall -- top link is joined to overhanging beam
end
myJoints[#myJoints + 1] = physics.newJoint( "pivot", prevLink, link[j], 121 + (i*34), 46 + (j*17) )
end
end
and here is the code for group
GUI:insert(myJoints);
i have my background image in the GUI group and it is covering the table.
I don't know if it is actually possible to insert table into a group
Any help please
Thanks in Advance!

You can't insert a table into a group using the "insert" method because that method is looking for a display object. Try calling GUI.myJoints = myJoints. Also keep in mind that your table just references your display objects, which is different from having them in a group.

select query with join is selecting data slowly from database in android

i have select query as follows
SELECT DISTINCT tt.firstname,
tt.lastname,
tc.caseid,
tt.courtcode AS courtid,
tcou.courtname,
(SELECT COUNT(*)
FROM tblcasetrafficticketlink
WHERE caseid = tc.caseid) AS ticketcount,
Max(tt.violationdate) AS violationdate,
( tt.address1
|| ','
|| tt.address2 ) AS address,
tt.city,
tt.state,
tt.zip,
tt.dob,
tt.sex
FROM tblcase tc
LEFT OUTER JOIN tblcasetrafficticketlink tcttl
ON tc.caseid = tcttl.caseid
LEFT OUTER JOIN tbltraffictickets tt
ON tcttl.courtid = tt.courtcode
AND tt.ticketnumber = tcttl.ticketnumber
AND ( tcttl.ticketextension = tt.ticketnumberex
OR tt.ticketnumberex IS NULL )
LEFT OUTER JOIN tblcourts tcou
ON tcou.courtid = tt.courtcode
WHERE tc.casetype = 'TRAFFIC'
AND tc.caseid<='"+recent_min_caseID+"'
GROUP BY tc.caseid,
tt.firstname,
tt.lastname,
tt.dob,
tt.sex,
tt.courtcode,
tcou.courtname,
tt.city,
tt.state,
tt.zip,
tc.casestatus,
tt.address1,
tt.address2
ORDER BY tc.caseid DESC
LIMIT 100;
this is taking much time to get data. can anybody help to improve performance.Here PRAGMA is useful? if so how? if not, tell me the way to fix this issue.

I've found that SQLite on Android seems to have some... unexpected quirks. In my case, it turned out that doing a straight query like select * from Foo where Bar is null was MUCH slower than selecting only the IDs and then fetching each row by ID individually. YMMV.