I have db with scheme
1. _id
2. word
And i have ArrayList with for example 5 words (a1, a2, a3, a4, a5)
What is the best way to construct query to get words from DB which don't contain words from ArrayList?
Sowthing like
Select * from MYTABLE where WORD not in "all words from
ArrayList"
Build a string representing the set of words, and use that as an argument to the query.
StringBuilder wordSet = new StringBuilder();
wordSet.append('(');
for( String word : wordsList )
{
if(wordSet.length() > 1)
wordSet.append(',');
wordSet.append(word);
}
wordSet.append(')');
Pseudo Query
Select * from mytable
Use the except operator against a selection containing words in array list
http://en.wikipedia.org/wiki/Set_operations_(SQL)#EXCEPT_operator
Related
My Select query is breaking of single inverted comma in the where clause string like (select * from where Col_Name in(?),new String []{list});
and list ="'abc','tyur','iop','nj'd','sjc'jskj'";
please let me know if there is any workaround for the above-mentioned issue.
You need to escape the ' character before passing it in the query.
Replace ' with ''(two single quotes) in your string.
Here is a simple string sanitizer for sql queries.
public static String sanitizeSqlString(String text) {
return text !=null ? text.replace("\'", "\'\'")
.replace("\"", "\"\"")
.replace("`", "``")
.replace("\\", "\\\\") : text;
}
You need to sanitize each element by iterating through the list.
I have a rather big query that is returning data when executed outside android while returning nothing when executed within android.
I split the query in several pieces and determined that the union was ok.
I tried on a smaller set of data with the same behavior.
I've tested with different hardware and API versions.
I'm using the rawQuery method with constant values.
http://developer.android.com/reference/android/database/sqlite/SQLiteDatabase.html#rawQuery(java.lang.String, java.lang.String[])
This query was meant to replace a FULL OUTER JOIN which is not currently supported.
SELECT IFNULL(stype, gtype) AS type, IFNULL(sdate, gdate) AS date, IFNULL(sroute, groute) AS route FROM (
SELECT sp.type AS stype, sp.date AS sdate, -1 AS gtype, gp.date AS gdate, sp.route AS sroute, gp.route AS groute
FROM Sensor_Point AS sp LEFT JOIN GPS_Point AS gp ON gp._id IS NULL AND sp.sent=0 AND sp.route=gp.route AND sp.route=1
UNION ALL
SELECT sp.type AS stype, sp.date AS sdate, -1 AS gtype, gp.date AS gdate, sp.route AS sroute, gp.route AS groute
FROM GPS_Point AS gp LEFT JOIN Sensor_Point AS sp ON sp._id IS NULL AND gp.sent=0 AND sp.route=gp.route AND gp.route=1
) WHERE route=1 ORDER BY date ASC LIMIT 255
Any hints would be greatly appreciated.
Update:
Look's like the problem is finally with the query parameters, if I set it this way:
String[] args = new String[3];
args[0] = args[1] = args[2] = "1";
Cursor data dataBase.rawQuery(SELECT_POINTS, args);
It doesn't work, while it works when hardcoding values directly in the query.
Cursor data = dataBase.rawQuery(SELECT_POINTS, null);
In the Android database API, all query parameters are strings.
(This is a horrible design mistake.)
Your query corresponds to:
... AND sp.route='1'
Try to convert the parameter strings back into a number like this:
... AND sp.route = CAST(? AS INT)
or just put the number directly into the query string.
I'm working on an android app that uses sugarORM. I want to get a multiple items that match the ids in a list.
However when i call
findWithQuery(A.class, "SELECT * FROM <table> WHERE <column> in (?)", "1,2,3")
I always get an empty list(although I double checked the query with SQLite DB Browser and it worked).
Splitting this query into multiple findById seems inefficient. Any thoughts on getting WHERE IN to work using SugarORM?
After more attempts I found that there is a problem with replacing the placeholders.
Switching from:
findWithQuery(A.class, "SELECT * FROM <table> WHERE <column> in (?)", "1,2,3")
To:
findWithQuery(A.class, "SELECT * FROM <table> WHERE <column> in (1,2,3)", null)
fixes the issue.
The issue is that SQLite escapes the arguments "1,2,3" and turns it into a single value that is then used to replace the single ? placeholder in your query string. The correct way to supply multiple arguments would be to have a placeholder for every individual argument. Your original line of code would then have to change to:
findWithQuery(A.class, "SELECT * FROM <table> WHERE <column> in (?,?,?)", new String[] { "1","2","3" })
You later pointed out that the number of arguments is dynamic. This you can easily be accomplished by generating the query (the where clause in particular) at runtime based on the arguments that you want to query for.
For the most general case, it only takes a few lines of code to do so:
final String[] args = new String[] { /* ... */ };
final String query = "SELECT * FROM <table> WHERE <column> in " +
"(" + TextUtils.join(",", Collections.nCopies(args.length, "?")) + ")";
final List<A> result = A.findWithQuery(A.class, query, args);
(note that you could take a shortcut and inject the arguments directly into the query string - instead of using placeholders - but then you'll loose SQLite's built-in escaping, so I decided against that)
All that's left to do is to generate a String[] out of your arguments. A simple helper method like this should cover most scenarios:
static String[] toStringArray(Object... args) {
final String[] array = new String[args.length];
for (int i = 0; i < args.length; i++) array[i] = args[i].toString();
return array;
}
You'll probably want to add some null checks in there and potentially set up a few overloads if you plan on using primitive arrays as arguments.
Disclaimer: I typed everything straight into the browser, so no guarantees that everything works and the first try. :)
I have a rather big query that is returning data when executed outside android while returning nothing when executed within android.
I split the query in several pieces and determined that the union was ok.
I tried on a smaller set of data with the same behavior.
I've tested with different hardware and API versions.
I'm using the rawQuery method with constant values.
http://developer.android.com/reference/android/database/sqlite/SQLiteDatabase.html#rawQuery(java.lang.String, java.lang.String[])
This query was meant to replace a FULL OUTER JOIN which is not currently supported.
SELECT IFNULL(stype, gtype) AS type, IFNULL(sdate, gdate) AS date, IFNULL(sroute, groute) AS route FROM (
SELECT sp.type AS stype, sp.date AS sdate, -1 AS gtype, gp.date AS gdate, sp.route AS sroute, gp.route AS groute
FROM Sensor_Point AS sp LEFT JOIN GPS_Point AS gp ON gp._id IS NULL AND sp.sent=0 AND sp.route=gp.route AND sp.route=1
UNION ALL
SELECT sp.type AS stype, sp.date AS sdate, -1 AS gtype, gp.date AS gdate, sp.route AS sroute, gp.route AS groute
FROM GPS_Point AS gp LEFT JOIN Sensor_Point AS sp ON sp._id IS NULL AND gp.sent=0 AND sp.route=gp.route AND gp.route=1
) WHERE route=1 ORDER BY date ASC LIMIT 255
Any hints would be greatly appreciated.
Update:
Look's like the problem is finally with the query parameters, if I set it this way:
String[] args = new String[3];
args[0] = args[1] = args[2] = "1";
Cursor data dataBase.rawQuery(SELECT_POINTS, args);
It doesn't work, while it works when hardcoding values directly in the query.
Cursor data = dataBase.rawQuery(SELECT_POINTS, null);
In the Android database API, all query parameters are strings.
(This is a horrible design mistake.)
Your query corresponds to:
... AND sp.route='1'
Try to convert the parameter strings back into a number like this:
... AND sp.route = CAST(? AS INT)
or just put the number directly into the query string.
I'm using the QueryBuilder to construct the inner SQL that later is used in a raw SQL to avoid escaping invalid characters manually.
SelectArg friendsIN = new SelectArg(friendsUsernames);
QueryBuilder<MyObject, Integer> qb = myObjectDao.queryBuilder();
qb.selectRaw("username", "MAX(time) AS latestTime").groupBy("username").where()
.in("username", friendsIN);
String innerSelect = pq.getStatement();
friendsUsernames is defined as ArrayList<String>.
Then I use the innerSelect to build the outer select:
String select = "SELECT w.id FROM (" + innerSelect +") AS x INNER JOIN myObject AS w on w.username = x.username AND w.time = x.latestTime";
GenericRawResults<String[]> results = myObjectDao.queryRaw(select);
But, as expected, the innerString has '?' and when I call queryRaw on myObjectDao I don't get any result. I tried to give friendsUsername as an array to queryRaw:
GenericRawResults<String[]> results =
myObjectrDao.queryRaw(select,
friendsUsernames.toArray(new String[friendsUsernames.size()]));
But I get the following error:
android.database.sqlite.SQLiteBindOrColumnIndexOutOfRangeException:
bind or column index out of range: handle 0x17a22e8
Any suggestions on how to accomplish this kind of queries with OrmLite?
Yeah that's not going to work. There is only one ? in your query and yet you are trying to pass in an array of user-names. There must be a 1-to-1 correspondence between the number of ? SQL arguments and the number of arguments passed to the queryRaw(...) method exactly.
If the friendsUsernames is a fixed size then you should be able to do something like the following which will generate SQL something like "in (?, ?, ?, ?)":
List<SelectArg> friendsInList = new ArrayList<SelectArg>();
for (int i = 0; i < NUM_FRIENDS; i++) {
// it doesn't matter what the value is since you just want the ?
fieldsInList.add(new SelectArg());
}
...in("name", friendsInList);
However if the list of names is dynamic then you are going to have to do this on the fly since, again, the number of ? must match the number of arguments passed to the queryRaw(...) method exactly.