I have the following code...
protected long getNumQueuedChunks(boolean distinctEntries) throws Exception {
SQLiteDatabase db = null;
try {
db = dbhelper.getReadableDatabase();
String whereClause = C_STATUS + " = ? AND " + C_NUM_FAILURES + " < ?";
String[] whereArgs = new String[] {STATUS_AWAITING_PROCESSING, 10};
long count = DatabaseUtils.queryNumEntries(db, QUEUE_TABLE_NAME, whereClause, whereArgs);
return count;
}
finally {
try {
db.close();
}
catch(Exception ignore) {
}
}
}
...which works fine if I want to return the total amount of rows that match the WHERE condition.
However, I would like to only count records that have distinct/unique combinations of data across these 3 columns: C_URI, C_BYTE_START_NUM and C_NUM_BYTES.
I know I could do something like...
String[] columns = {C_URI, C_BYTE_START_NUM, C_NUM_BYTES};
String whereClause = C_STATUS + " = ? AND " + C_NUM_FAILURES + " < ?";
String[] whereArgs = new String[] {STATUS_AWAITING_PROCESSING, "10"};
Cursor c = db.query(true, QUEUE_TABLE_NAME, columns, whereClause, whereArgs, null, null, null, null);
int count = c.getCount();
...but I am hoping there is a more efficient way to perform a distinct count in this situation??
Just to add clarity, if I have this data in my table...
C_URI | C_BYTE_START_NUM | C_NUM_BYTES
1.jpg | 0 | 1024
1.jpg | 1024 | 1999
2.jpg | 0 | 500
2.jpg | 0 | 500
...the result of the distinct count should be 3.
NB - I have seen a similar requirement described here (second answer) but that doesn't help me as I am wanting to do a distinct count across 3 columns rather than just one.
The most efficient way of counting records is to let the database do this:
SELECT COUNT(*)
FROM (SELECT DISTINCT Uri,
ByteStartNum,
NumBytes
FROM QueueTable)
(With the separate subquery, it does not matter if you use DISTINCT or GROUP BY over the three columns.)
This query does not fit into the constraints of one of the helper functions like query or queryNumEntries, so you have to construct the entire SQL statement by hand:
long getNumQueuedChunks() {
SQLiteDatabase db = dbhelper.getReadableDatabase();
try {
String query = "SELECT COUNT(*) FROM " +
"(SELECT DISTINCT " + C_URI + "," + C_BYTE_START_NUM + "," + C_NUM_BYTES +
" FROM " + QUEUE_TABLE_NAME +
" WHERE " + C_STATUS + " = ?" +
" AND " + C_NUM_FAILURES + " < 10)";
String[] args = new String[] { STATUS_AWAITING_PROCESSING };
return DatabaseUtils.longForQuery(db, query, args);
} finally {
db.close();
}
}
Have you tried the SQLiteDatabase.rawQuery() method? You can put a raw SQL query in it, for example, something like:
select distinct C_URI, C_BYTE_START_NUM, C_NUM_BYTES from MyTable
The method returns a Cursor, and you can immediately get the count from the cursor object. Of course, you can specify a where clause if you want to as well. Then free up the Cursor once you got your count.
Related
I have some code like this:
public void gameOverCheck() {
SQLiteDatabase database = this.getWritableDatabase();
database.execSQL("SELECT " + COL_ROLE + " COUNT");
database.close();
}
in android. And would like to count the values of COL_ROLE (which has one of two possible values (mafia, civilian)). So if the number of Mafia >= Civilian game = mafias win. If Mafias = 0, game = civilian won. I am struggling with the SQL command to do the first part, am I supposed to group the values?
Try this:
Cursor mCount= db.rawQuery("select count(*) from your_table where " + COL_ROLE + " = 'mafia'", null);
mCount.moveToFirst();
int count = mCount.getInt(0);
mCount.close();`
I'm attempting to do the following SQL query within Android:
String names = "'name1', 'name2"; // in the code this is dynamically generated
String query = "SELECT * FROM table WHERE name IN (?)";
Cursor cursor = mDb.rawQuery(query, new String[]{names});
However, Android does not replace the question mark with the correct values. I could do the following, however, this does not protect against SQL injection:
String query = "SELECT * FROM table WHERE name IN (" + names + ")";
Cursor cursor = mDb.rawQuery(query, null);
How can I get around this issue and be able to use the IN clause?
A string of the form "?, ?, ..., ?" can be a dynamically created string and safely put into the original SQL query (because it is a restricted form that does not contain external data) and then the placeholders can be used as normal.
Consider a function String makePlaceholders(int len) which returns len question-marks separated with commas, then:
String[] names = { "name1", "name2" }; // do whatever is needed first
String query = "SELECT * FROM table"
+ " WHERE name IN (" + makePlaceholders(names.length) + ")";
Cursor cursor = mDb.rawQuery(query, names);
Just make sure to pass exactly as many values as places. The default maximum limit of host parameters in SQLite is 999 - at least in a normal build, not sure about Android :)
Here is one implementation:
String makePlaceholders(int len) {
if (len < 1) {
// It will lead to an invalid query anyway ..
throw new RuntimeException("No placeholders");
} else {
StringBuilder sb = new StringBuilder(len * 2 - 1);
sb.append("?");
for (int i = 1; i < len; i++) {
sb.append(",?");
}
return sb.toString();
}
}
Short example, based on answer of user166390:
public Cursor selectRowsByCodes(String[] codes) {
try {
SQLiteDatabase db = getReadableDatabase();
SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
String[] sqlSelect = {COLUMN_NAME_ID, COLUMN_NAME_CODE, COLUMN_NAME_NAME, COLUMN_NAME_PURPOSE, COLUMN_NAME_STATUS};
String sqlTables = "Enumbers";
qb.setTables(sqlTables);
Cursor c = qb.query(db, sqlSelect, COLUMN_NAME_CODE+" IN (" +
TextUtils.join(",", Collections.nCopies(codes.length, "?")) +
")", codes,
null, null, null);
c.moveToFirst();
return c;
} catch (Exception e) {
Log.e(this.getClass().getCanonicalName(), e.getMessage() + e.getStackTrace().toString());
}
return null;
}
Sadly there's no way of doing that (obviously 'name1', 'name2' is not a single value and can therefore not be used in a prepared statement).
So you will have to lower your sights (e.g. by creating very specific, not reusable queries like WHERE name IN (?, ?, ?)) or not using stored procedures and try to prevent SQL injections with some other techniques...
As suggest in accepted answer but without using custom function to generate comma-separated '?'. Please check code below.
String[] names = { "name1", "name2" }; // do whatever is needed first
String query = "SELECT * FROM table"
+ " WHERE name IN (" + TextUtils.join(",", Collections.nCopies(names.length, "?")) + ")";
Cursor cursor = mDb.rawQuery(query, names);
You can use TextUtils.join(",", parameters) to take advantage of sqlite binding parameters, where parameters is a list with "?" placeholders and the result string is something like "?,?,..,?".
Here is a little example:
Set<Integer> positionsSet = membersListCursorAdapter.getCurrentCheckedPosition();
List<String> ids = new ArrayList<>();
List<String> parameters = new ArrayList<>();
for (Integer position : positionsSet) {
ids.add(String.valueOf(membersListCursorAdapter.getItemId(position)));
parameters.add("?");
}
getActivity().getContentResolver().delete(
SharedUserTable.CONTENT_URI,
SharedUserTable._ID + " in (" + TextUtils.join(",", parameters) + ")",
ids.toArray(new String[ids.size()])
);
Actually you could use android's native way of querying instead of rawQuery:
public int updateContactsByServerIds(ArrayList<Integer> serverIds, final long groupId) {
final int serverIdsCount = serverIds.size()-1; // 0 for one and only id, -1 if empty list
final StringBuilder ids = new StringBuilder("");
if (serverIdsCount>0) // ambiguous "if" but -1 leads to endless cycle
for (int i = 0; i < serverIdsCount; i++)
ids.append(String.valueOf(serverIds.get(i))).append(",");
// add last (or one and only) id without comma
ids.append(String.valueOf(serverIds.get(serverIdsCount))); //-1 throws exception
// remove last comma
Log.i(this,"whereIdsList: "+ids);
final String whereClause = Tables.Contacts.USER_ID + " IN ("+ids+")";
final ContentValues args = new ContentValues();
args.put(Tables.Contacts.GROUP_ID, groupId);
int numberOfRowsAffected = 0;
SQLiteDatabase db = dbAdapter.getWritableDatabase());
try {
numberOfRowsAffected = db.update(Tables.Contacts.TABLE_NAME, args, whereClause, null);
} catch (Exception e) {
e.printStackTrace();
}
dbAdapter.closeWritableDB();
Log.d(TAG, "updateContactsByServerIds() numberOfRowsAffected: " + numberOfRowsAffected);
return numberOfRowsAffected;
}
This is not Valid
String subQuery = "SELECT _id FROM tnl_partofspeech where part_of_speech = 'noun'";
Cursor cursor = SQLDataBase.rawQuery(
"SELECT * FROM table_main where part_of_speech_id IN (" +
"?" +
")",
new String[]{subQuery}););
This is Valid
String subQuery = "SELECT _id FROM tbl_partofspeech where part_of_speech = 'noun'";
Cursor cursor = SQLDataBase.rawQuery(
"SELECT * FROM table_main where part_of_speech_id IN (" +
subQuery +
")",
null);
Using ContentResolver
String subQuery = "SELECT _id FROM tbl_partofspeech where part_of_speech = 'noun' ";
final String[] selectionArgs = new String[]{"1","2"};
final String selection = "_id IN ( ?,? )) AND part_of_speech_id IN (( " + subQuery + ") ";
SQLiteDatabase SQLDataBase = DataBaseManage.getReadableDatabase(this);
SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
queryBuilder.setTables("tableName");
Cursor cursor = queryBuilder.query(SQLDataBase, null, selection, selectionArgs, null,
null, null);
In Kotlin you can use joinToString
val query = "SELECT * FROM table WHERE name IN (${names.joinToString(separator = ",") { "?" }})"
val cursor = mDb.rawQuery(query, names.toTypedArray())
I use the Stream API for this:
final String[] args = Stream.of("some","data","for","args").toArray(String[]::new);
final String placeholders = Stream.generate(() -> "?").limit(args.length).collect(Collectors.joining(","));
final String selection = String.format("SELECT * FROM table WHERE name IN(%s)", placeholders);
db.rawQuery(selection, args);
I'm attempting to do the following SQL query within Android:
String names = "'name1', 'name2"; // in the code this is dynamically generated
String query = "SELECT * FROM table WHERE name IN (?)";
Cursor cursor = mDb.rawQuery(query, new String[]{names});
However, Android does not replace the question mark with the correct values. I could do the following, however, this does not protect against SQL injection:
String query = "SELECT * FROM table WHERE name IN (" + names + ")";
Cursor cursor = mDb.rawQuery(query, null);
How can I get around this issue and be able to use the IN clause?
A string of the form "?, ?, ..., ?" can be a dynamically created string and safely put into the original SQL query (because it is a restricted form that does not contain external data) and then the placeholders can be used as normal.
Consider a function String makePlaceholders(int len) which returns len question-marks separated with commas, then:
String[] names = { "name1", "name2" }; // do whatever is needed first
String query = "SELECT * FROM table"
+ " WHERE name IN (" + makePlaceholders(names.length) + ")";
Cursor cursor = mDb.rawQuery(query, names);
Just make sure to pass exactly as many values as places. The default maximum limit of host parameters in SQLite is 999 - at least in a normal build, not sure about Android :)
Here is one implementation:
String makePlaceholders(int len) {
if (len < 1) {
// It will lead to an invalid query anyway ..
throw new RuntimeException("No placeholders");
} else {
StringBuilder sb = new StringBuilder(len * 2 - 1);
sb.append("?");
for (int i = 1; i < len; i++) {
sb.append(",?");
}
return sb.toString();
}
}
Short example, based on answer of user166390:
public Cursor selectRowsByCodes(String[] codes) {
try {
SQLiteDatabase db = getReadableDatabase();
SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
String[] sqlSelect = {COLUMN_NAME_ID, COLUMN_NAME_CODE, COLUMN_NAME_NAME, COLUMN_NAME_PURPOSE, COLUMN_NAME_STATUS};
String sqlTables = "Enumbers";
qb.setTables(sqlTables);
Cursor c = qb.query(db, sqlSelect, COLUMN_NAME_CODE+" IN (" +
TextUtils.join(",", Collections.nCopies(codes.length, "?")) +
")", codes,
null, null, null);
c.moveToFirst();
return c;
} catch (Exception e) {
Log.e(this.getClass().getCanonicalName(), e.getMessage() + e.getStackTrace().toString());
}
return null;
}
Sadly there's no way of doing that (obviously 'name1', 'name2' is not a single value and can therefore not be used in a prepared statement).
So you will have to lower your sights (e.g. by creating very specific, not reusable queries like WHERE name IN (?, ?, ?)) or not using stored procedures and try to prevent SQL injections with some other techniques...
As suggest in accepted answer but without using custom function to generate comma-separated '?'. Please check code below.
String[] names = { "name1", "name2" }; // do whatever is needed first
String query = "SELECT * FROM table"
+ " WHERE name IN (" + TextUtils.join(",", Collections.nCopies(names.length, "?")) + ")";
Cursor cursor = mDb.rawQuery(query, names);
You can use TextUtils.join(",", parameters) to take advantage of sqlite binding parameters, where parameters is a list with "?" placeholders and the result string is something like "?,?,..,?".
Here is a little example:
Set<Integer> positionsSet = membersListCursorAdapter.getCurrentCheckedPosition();
List<String> ids = new ArrayList<>();
List<String> parameters = new ArrayList<>();
for (Integer position : positionsSet) {
ids.add(String.valueOf(membersListCursorAdapter.getItemId(position)));
parameters.add("?");
}
getActivity().getContentResolver().delete(
SharedUserTable.CONTENT_URI,
SharedUserTable._ID + " in (" + TextUtils.join(",", parameters) + ")",
ids.toArray(new String[ids.size()])
);
Actually you could use android's native way of querying instead of rawQuery:
public int updateContactsByServerIds(ArrayList<Integer> serverIds, final long groupId) {
final int serverIdsCount = serverIds.size()-1; // 0 for one and only id, -1 if empty list
final StringBuilder ids = new StringBuilder("");
if (serverIdsCount>0) // ambiguous "if" but -1 leads to endless cycle
for (int i = 0; i < serverIdsCount; i++)
ids.append(String.valueOf(serverIds.get(i))).append(",");
// add last (or one and only) id without comma
ids.append(String.valueOf(serverIds.get(serverIdsCount))); //-1 throws exception
// remove last comma
Log.i(this,"whereIdsList: "+ids);
final String whereClause = Tables.Contacts.USER_ID + " IN ("+ids+")";
final ContentValues args = new ContentValues();
args.put(Tables.Contacts.GROUP_ID, groupId);
int numberOfRowsAffected = 0;
SQLiteDatabase db = dbAdapter.getWritableDatabase());
try {
numberOfRowsAffected = db.update(Tables.Contacts.TABLE_NAME, args, whereClause, null);
} catch (Exception e) {
e.printStackTrace();
}
dbAdapter.closeWritableDB();
Log.d(TAG, "updateContactsByServerIds() numberOfRowsAffected: " + numberOfRowsAffected);
return numberOfRowsAffected;
}
This is not Valid
String subQuery = "SELECT _id FROM tnl_partofspeech where part_of_speech = 'noun'";
Cursor cursor = SQLDataBase.rawQuery(
"SELECT * FROM table_main where part_of_speech_id IN (" +
"?" +
")",
new String[]{subQuery}););
This is Valid
String subQuery = "SELECT _id FROM tbl_partofspeech where part_of_speech = 'noun'";
Cursor cursor = SQLDataBase.rawQuery(
"SELECT * FROM table_main where part_of_speech_id IN (" +
subQuery +
")",
null);
Using ContentResolver
String subQuery = "SELECT _id FROM tbl_partofspeech where part_of_speech = 'noun' ";
final String[] selectionArgs = new String[]{"1","2"};
final String selection = "_id IN ( ?,? )) AND part_of_speech_id IN (( " + subQuery + ") ";
SQLiteDatabase SQLDataBase = DataBaseManage.getReadableDatabase(this);
SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
queryBuilder.setTables("tableName");
Cursor cursor = queryBuilder.query(SQLDataBase, null, selection, selectionArgs, null,
null, null);
In Kotlin you can use joinToString
val query = "SELECT * FROM table WHERE name IN (${names.joinToString(separator = ",") { "?" }})"
val cursor = mDb.rawQuery(query, names.toTypedArray())
I use the Stream API for this:
final String[] args = Stream.of("some","data","for","args").toArray(String[]::new);
final String placeholders = Stream.generate(() -> "?").limit(args.length).collect(Collectors.joining(","));
final String selection = String.format("SELECT * FROM table WHERE name IN(%s)", placeholders);
db.rawQuery(selection, args);
I am trying to write an SQL database request using .query instead of .rawQuery (i have been told it's more efficient, even though not everyone seem to agree with this...).
If I had to write it in SQL, it would be approximately something like this :
select COL_NAME, COL_COMMENTS, KEY_ROW_ID
from TABLE
where COL_CAT1 = myVariable1 or myVariable2 or ... myVariableN
or COL_CAT2 = myVariable1 or myVariable2 or .... myVariableN
or COL_CAT3 = myVariable1 or myVariable2 or.... myVariableN
I have tried this :
public Cursor findNameInTable(int myVariable1, int myVariable2, int myVariableN) {
String where = COL_CAT1 + " = ? OR " + COL_CAT2 + "=?";
String[] whereArgs = new String[] { Integer.toString(myVariable1), Integer.toString(myVariable2), Integer.toString(myVariableN)};
c = myDatabase
.query(DATABASE_TABLE, new String[] { KEY_ROWID, COL_NAME , COL_COMMENTS },
where,
whereArgs, null,
null, null);
return c;
}
The problem with this is that the system is doing this :
select .....
from .....
where COL_CAT1 = myVariable1
or COL_CAT2 = myVariable2
or ???? = myVariableN
and then it crashes because it expects to compare each variable with a new column, which is not what I want: I have more inputs variable than columns.
It's actually the " =?" which seems not to be appropriate, but no way to find how to write this kind of request, most of documentation is about rawQuery() and not query(). Thanks in advance.
Try this
public Cursor findNameInTable(int myVariable1, int myVariable2, ..., int myVariableN)
{
String inInterval = "(?,?,?,...,?)"; // N question mark altogether.
String where = COL_CAT1 + " IN " + inInterval
+ " OR " + COL_CAT2 + " IN " + inInterval
+ ...........
+ " OR " + COL_CATM + " IN " + inInterval;
int numberOfColumn = M; // The number of columns you have.
String[] whereArgs = new String[M * N];
for (int i = 0; i < M; i++)
{
whereArgs[i * N + 0] = Integer.toString(myVariable1);
whereArgs[i * N + 1] = Integer.toString(myVariable2);
whereArgs[i * N + 2] = Integer.toString(myVariable3);
........................
whereArgs[i * N + N - 1] = Integer.toString(myVariableN);
}
Cursor c = myDatabase
.query(DATABASE_TABLE, new String[] { KEY_ROWID, COL_NAME , COL_COMMENTS },
where,
whereArgs, null,
null, null);
return c;
}
Because you are creating an extensive query, you may want to consider using:
http://developer.android.com/reference/android/database/sqlite/SQLiteQueryBuilder.html
This will allow you to basically create a longer where clause. However; this should also theoretically be possible with a rawQuery with a StringBuilder, but in best practices its better to use the wrapper approach method.
I'm attempting to do the following SQL query within Android:
String names = "'name1', 'name2"; // in the code this is dynamically generated
String query = "SELECT * FROM table WHERE name IN (?)";
Cursor cursor = mDb.rawQuery(query, new String[]{names});
However, Android does not replace the question mark with the correct values. I could do the following, however, this does not protect against SQL injection:
String query = "SELECT * FROM table WHERE name IN (" + names + ")";
Cursor cursor = mDb.rawQuery(query, null);
How can I get around this issue and be able to use the IN clause?
A string of the form "?, ?, ..., ?" can be a dynamically created string and safely put into the original SQL query (because it is a restricted form that does not contain external data) and then the placeholders can be used as normal.
Consider a function String makePlaceholders(int len) which returns len question-marks separated with commas, then:
String[] names = { "name1", "name2" }; // do whatever is needed first
String query = "SELECT * FROM table"
+ " WHERE name IN (" + makePlaceholders(names.length) + ")";
Cursor cursor = mDb.rawQuery(query, names);
Just make sure to pass exactly as many values as places. The default maximum limit of host parameters in SQLite is 999 - at least in a normal build, not sure about Android :)
Here is one implementation:
String makePlaceholders(int len) {
if (len < 1) {
// It will lead to an invalid query anyway ..
throw new RuntimeException("No placeholders");
} else {
StringBuilder sb = new StringBuilder(len * 2 - 1);
sb.append("?");
for (int i = 1; i < len; i++) {
sb.append(",?");
}
return sb.toString();
}
}
Short example, based on answer of user166390:
public Cursor selectRowsByCodes(String[] codes) {
try {
SQLiteDatabase db = getReadableDatabase();
SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
String[] sqlSelect = {COLUMN_NAME_ID, COLUMN_NAME_CODE, COLUMN_NAME_NAME, COLUMN_NAME_PURPOSE, COLUMN_NAME_STATUS};
String sqlTables = "Enumbers";
qb.setTables(sqlTables);
Cursor c = qb.query(db, sqlSelect, COLUMN_NAME_CODE+" IN (" +
TextUtils.join(",", Collections.nCopies(codes.length, "?")) +
")", codes,
null, null, null);
c.moveToFirst();
return c;
} catch (Exception e) {
Log.e(this.getClass().getCanonicalName(), e.getMessage() + e.getStackTrace().toString());
}
return null;
}
Sadly there's no way of doing that (obviously 'name1', 'name2' is not a single value and can therefore not be used in a prepared statement).
So you will have to lower your sights (e.g. by creating very specific, not reusable queries like WHERE name IN (?, ?, ?)) or not using stored procedures and try to prevent SQL injections with some other techniques...
As suggest in accepted answer but without using custom function to generate comma-separated '?'. Please check code below.
String[] names = { "name1", "name2" }; // do whatever is needed first
String query = "SELECT * FROM table"
+ " WHERE name IN (" + TextUtils.join(",", Collections.nCopies(names.length, "?")) + ")";
Cursor cursor = mDb.rawQuery(query, names);
You can use TextUtils.join(",", parameters) to take advantage of sqlite binding parameters, where parameters is a list with "?" placeholders and the result string is something like "?,?,..,?".
Here is a little example:
Set<Integer> positionsSet = membersListCursorAdapter.getCurrentCheckedPosition();
List<String> ids = new ArrayList<>();
List<String> parameters = new ArrayList<>();
for (Integer position : positionsSet) {
ids.add(String.valueOf(membersListCursorAdapter.getItemId(position)));
parameters.add("?");
}
getActivity().getContentResolver().delete(
SharedUserTable.CONTENT_URI,
SharedUserTable._ID + " in (" + TextUtils.join(",", parameters) + ")",
ids.toArray(new String[ids.size()])
);
Actually you could use android's native way of querying instead of rawQuery:
public int updateContactsByServerIds(ArrayList<Integer> serverIds, final long groupId) {
final int serverIdsCount = serverIds.size()-1; // 0 for one and only id, -1 if empty list
final StringBuilder ids = new StringBuilder("");
if (serverIdsCount>0) // ambiguous "if" but -1 leads to endless cycle
for (int i = 0; i < serverIdsCount; i++)
ids.append(String.valueOf(serverIds.get(i))).append(",");
// add last (or one and only) id without comma
ids.append(String.valueOf(serverIds.get(serverIdsCount))); //-1 throws exception
// remove last comma
Log.i(this,"whereIdsList: "+ids);
final String whereClause = Tables.Contacts.USER_ID + " IN ("+ids+")";
final ContentValues args = new ContentValues();
args.put(Tables.Contacts.GROUP_ID, groupId);
int numberOfRowsAffected = 0;
SQLiteDatabase db = dbAdapter.getWritableDatabase());
try {
numberOfRowsAffected = db.update(Tables.Contacts.TABLE_NAME, args, whereClause, null);
} catch (Exception e) {
e.printStackTrace();
}
dbAdapter.closeWritableDB();
Log.d(TAG, "updateContactsByServerIds() numberOfRowsAffected: " + numberOfRowsAffected);
return numberOfRowsAffected;
}
This is not Valid
String subQuery = "SELECT _id FROM tnl_partofspeech where part_of_speech = 'noun'";
Cursor cursor = SQLDataBase.rawQuery(
"SELECT * FROM table_main where part_of_speech_id IN (" +
"?" +
")",
new String[]{subQuery}););
This is Valid
String subQuery = "SELECT _id FROM tbl_partofspeech where part_of_speech = 'noun'";
Cursor cursor = SQLDataBase.rawQuery(
"SELECT * FROM table_main where part_of_speech_id IN (" +
subQuery +
")",
null);
Using ContentResolver
String subQuery = "SELECT _id FROM tbl_partofspeech where part_of_speech = 'noun' ";
final String[] selectionArgs = new String[]{"1","2"};
final String selection = "_id IN ( ?,? )) AND part_of_speech_id IN (( " + subQuery + ") ";
SQLiteDatabase SQLDataBase = DataBaseManage.getReadableDatabase(this);
SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
queryBuilder.setTables("tableName");
Cursor cursor = queryBuilder.query(SQLDataBase, null, selection, selectionArgs, null,
null, null);
In Kotlin you can use joinToString
val query = "SELECT * FROM table WHERE name IN (${names.joinToString(separator = ",") { "?" }})"
val cursor = mDb.rawQuery(query, names.toTypedArray())
I use the Stream API for this:
final String[] args = Stream.of("some","data","for","args").toArray(String[]::new);
final String placeholders = Stream.generate(() -> "?").limit(args.length).collect(Collectors.joining(","));
final String selection = String.format("SELECT * FROM table WHERE name IN(%s)", placeholders);
db.rawQuery(selection, args);