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.
Related
I need a query that brings all the parents whose children meet a certain criteria.
So far this is giving me something different than expected:
#Transaction
#Query("SELECT * FROM piece_unit_table put WHERE (SELECT et.date_of_creation FROM expense_table et WHERE et.piece_unit_parent_id = put.piece_unit_id) = :dateOfExpenseCreation AND project_id = :projectId")
public abstract LiveData<List<PieceUnit>> getPieceUnitsWhereDateOfExpenseCreation(long dateOfExpenseCreation, int projectId);
A more readable version of the same code above:
SELECT *
FROM piece_unit_table put
WHERE (
SELECT et.date_of_creation
FROM expense_table et
WHERE et.piece_unit_parent_id = put.piece_unit_id
) = :dateOfExpenseCreation
AND project_id = :projectId
At first I thought I got a jackpot with that one because it gave me responses on the first try (I usually spend a whole day just thinking about the structure of the query, I hate them), I never gave it too much thought, but the days passed by and it stopped giving me responses, so I'm guessing that maybe, the query was comparing some other dates inside the WHERE clause, more precisely, the dates on which the pieces where created.
Now that I reread it again it looks like a pretty bad query...
The way in which I'm storing dates (from the children side):
public void insertExpense(Expense expense) {
long now = Converters.dateToTimestamp(LocalDate.now());
expense .setDate_of_creation(now);
long edited = System.currentTimeMillis();
expense .setLast_edited(edited);
Log.println(Log.WARN, TAG, "insertExpense: date of creation is: " + expense.getDate_of_creation());
Log.println(Log.WARN, TAG, "insertExpense: expense project is: " + expense.getParent_project_id());
Log.println(Log.WARN, TAG, "insertExpense: expense piece parent is: " + expense.getPiece_unit_parent_id());
insert(expense);
}
The observer side:
Log.println(Log.ERROR, TAG, "getPieceUnitGroupedByExpenseProductsAtDateAndProject: specific date is: " + specificDate);
Log.d(TAG, "getPieceUnitGroupedByExpenseProductsAtDateAndProject: project id is: " + project);
MyObserver
.observeOnce(
pieceUnitRepository.getPieceUnitsWhereDateOfExpenseCreation(
specificDate,
project
),
pieceUnits ->
{
Log.d(TAG, "getPieceUnitGroupedByExpenseProductsAtDateAndProject: piece units are: " + pieceUnits);
if (pieceUnits != null && pieceUnits.size() > 0) {
PieceUnit p = pieceUnits.get(0);
Log.println(Log.WARN, TAG, "getPieceUnitGroupedByExpenseProductsAtDateAndProject: Hello there ;) : " + p.getBeginning_date());
}
The Logd's:
insertExpense: date of creation is: 18469
insertExpense: expense project is: 1
insertExpense: expense piece parent is: 4
getPieceUnitGroupedByExpenseProductsAtDateAndProject: specific date is: 18469
getPieceUnitGroupedByExpenseProductsAtDateAndProject: project id is: 1
getPieceUnitGroupedByExpenseProductsAtDateAndProject: piece units are: []
I'm not asking for a full solution, but any input could point me in the right direction, so thanks in advance.
Final answer (from second update):
SELECT
put.*
FROM piece_unit_table put
WHERE
EXISTS(
SELECT
1
FROM
expense_table et
WHERE
et.date_of_creation = :dateOfExpenseCreation AND et.piece_unit_parent_id = piece_unit_id
) AND
put.project_id = :projectId
EDITS
First answer :
In SQL there seems to be a function that helps on these cases:
all or not exist
https://stackoverflow.com/a/42439405/11214643
In the SQLite case there doesn't seem to be a direct equivalence, and every solution seems to be a case by case workaround depending on the type of clause.
In my case I LEFT JOIN-ed the children table, but group by-ing it before the join to avoid repeated rows on the left table.
As is expected, it was during the child table sub-query, that I filtered the table by their date condition
SELECT put.*
FROM piece_unit_table put
LEFT JOIN(
SELECT
piece_unit_parent_id
FROM
expense_table et
WHERE
et.date_of_creation = :dateOfExpenseCreation
GROUP BY
et.piece_unit_parent_id
) et1
ON
et1.piece_unit_parent_id = put.piece_unit_id
WHERE
put.project_id = :projectId
UPDATE:
It seems that behind curtains(either be SQLite or the ROOM interface), the LEFT JOIN is happening before the sub-query executes its own WHERE clause, as a result, the query is giving me parents, even when there are no children that meet the criteria, so the solution was to bring an additional column from the child temp table to the 'front', and check for it's non null-ability.
SELECT
put.*,
et1.puId AS expPuId
FROM piece_unit_table put
LEFT JOIN(
SELECT
piece_unit_parent_id AS puId
FROM
expense_table et
WHERE
et.date_of_creation = :dateOfExpenseCreation
GROUP BY
et.piece_unit_parent_id
) et1
ON
et1.puId = put.piece_unit_id
WHERE
put.project_id = :projectId AND expPuId NOT NULL
UPDATE 2:
Thanks to #forpas
The EXISTS and NOT EXISTS operators are in fact supported by SQLite, also, what was bringing me parents even when no children met the criteria was the second WHERE clause that was applied directly to the left table, but even if there was no clause applied to this table, it would've still gave me answers, because that's how LEFT JOIN works, if there are no matches it fills them with NULL's.
Here is a query that has the expected result, but does it better.
SELECT
put.*
FROM piece_unit_table put
WHERE
EXISTS(
SELECT
1
FROM
expense_table et
WHERE
et.date_of_creation = :dateOfExpenseCreation AND et.piece_unit_parent_id = piece_unit_id
) AND
put.project_id = :projectId
This is the structure and data of my table funco inside database your.db (SQLite):
Id Disp Tp
1 Ball 2
2 Light 1
3 Sea 4
This is my code:
var db = SQLiteDatabase.openDatabase(this.filesDir.path +
"/your.db",null, SQLiteDatabase.OPEN_READWRITE)
val c = db.rawQuery("Select Id, Disp, Tp From Funco Where Id<=2;",null)
var stat = c.moveToFirst()
var result=""
while (stat) {
val mId = c.getInt(c.getColumnIndex("Id"))
val mDisp = c.getString(c.getColumnIndex("Disp"))
val mTp = c.getInt(c.getColumnIndex("Tp"))
result += "$mId $mDisp $mTp | "
stat = c.moveToNext()
}
c.close()
db.close()
The result value:
1 Ball 2 | 2 Light 1 |
If I replace my second line for
val c = db.rawQuery("Select ?, ?, ? From Funco Where ?<=2;"
,arrayOf("Id","Disp","Tp","Id"))
There is no error raised, but the cursor is empty!
Why?
Update:
The #tynn answer is right. I think that the documentation is subtle.
I think that compiler shoud be throw an error and not just return empty cursor.
In the same flavor, one can write
val c = db.query("funco",arrayOf("Id","Disp","Tp"),"Id<=?",
arrayOf("2"),null,null,null)
But below code fails
val c = db.query("funco",arrayOf("Id","Disp","Tp"),"?<=?",
arrayOf("id","2"),null,null,null)
As the documentation states:
selectionArgs String: You may include ?s in where clause in the query, which will be replaced by the values from selectionArgs. The values will be bound as Strings.
The question marks are there to bind different values to a precompiled SQL query. This functionality is not suitable for configuring the columns to be used in the query. Your first approach is the correct one. You could make the 2 in it dynamic though:
db.rawQuery("Select Id, Disp, Tp From Funco Where Id<=?;", arrayOf("2"))
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.
I have this SQL.
select sum(distance) AS distance FROM RoadTravelTableFile where checkBoxBusiness ='1' and plate_Number = 'AAA567'"
I have seen this simple query for raw sql in the Ormlite document.
long maxUnits = orderDao.queryRawValue("select max(units) from orders");
With that example, I coded my sql like this and it works.
distance = (int) getHelper().getRoadTravelTableFileIntegerDao().queryRawValue("SELECT SUM(distance) FROM RoadTravelTableFile where checkBoxBusiness = '1' and plate_Number ='AAA567' ");
But I have a problem, How can you make the checkBoxBusiness and plate_Number value as a parameter?
Replace current values with ? and add arguments to the queryRawValue method.
Integer checkBoxBusiness = 1;
String plateNumber = "AAA567";
distance = (int) getHelper()
.getRoadTravelTableFileIntegerDao()
.queryRawValue("SELECT SUM(distance) FROM RoadTravelTableFile where checkBoxBusiness = ? and plate_Number = ?", checkBoxBusiness, plateNumber);
im getting data from database which match any prefex how to add % on bothside of variable? below is my query i want to add '"+School_name+"' to this '%"+School_name+"%' how to do that?
Cursor mCursor3 = 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 sch.name like '"+School_name+"'");