How to Use The Limit Argument in an Sqlite Query with Android

How to use the LIMIT argument in an SQLite Query with Android

Order by id DESC Limit 1:

db.query("table", null, "column=?", new String[]{"value"}, null, null, "id DESC", "1");

Using the LIMIT statement in a SQLite query

The equals (=) operator is not used with the LIMIT clause. Remove it.

Here's an example LIMIT query:

SELECT column FROM table ORDER BY somethingelse LIMIT 5, 10

Or:

SELECT column FROM table ORDER BY somethingelse LIMIT 10

In your case, the correct statement would be:

return wDb.query(TABELANOME, new String[] {IDTIT, TAREFATIT, SUMARIOTIT}, CONCLUIDOTIT + "=1", null, null, null, null, String.valueOf(limite));

Take a look here at the SQLite select syntax: http://www.sqlite.org/syntaxdiagrams.html#select-stmt

This image is rather useful: http://www.sqlite.org/images/syntax/select-stmt.gif

What is the limit of SQL variables one can specify in a single execSQL query

The limit is hardcoded in sqlite3.c and is set to 999. Unfortunately it can be changed but only at compile time. Here are the relevant snippets:

/*
** The maximum value of a ?nnn wildcard that the parser will accept.
*/
#ifndef SQLITE_MAX_VARIABLE_NUMBER
# define SQLITE_MAX_VARIABLE_NUMBER 999
#endif

/*
** The datatype ynVar is a signed integer, either 16-bit or 32-bit.
** Usually it is 16-bits.  But if SQLITE_MAX_VARIABLE_NUMBER is greater
** than 32767 we have to make it 32-bit.  16-bit is preferred because
** it uses less memory in the Expr object, which is a big memory user
** in systems with lots of prepared statements.  And few applications
** need more than about 10 or 20 variables.  But some extreme users want
** to have prepared statements with over 32767 variables, and for them
** the option is available (at compile-time).
*/
#if SQLITE_MAX_VARIABLE_NUMBER<=32767
typedef i16 ynVar;
#else
typedef int ynVar;
#endif

Is there any limit on sqlite query size?

Roughly speaking the default limit is 1,000,000 bytes or 1,000,000 characters, so unless your 'students' are over 100,000 characters each your statement should be fine.

The following is taken from http://www.sqlite.org/limits.html

Maximum Length Of An SQL Statement

The maximum number of bytes in the text of an SQL statement is limited to SQLITE_MAX_SQL_LENGTH which defaults to 1000000. You can redefine this limit to be as large as the smaller of SQLITE_MAX_LENGTH and 1073741824.

If an SQL statement is limited to be a million bytes in length, then obviously you will not be able to insert multi-million byte strings by embedding them as literals inside of INSERT statements. But you should not do that anyway. Use host parameters for your data. Prepare short SQL statements like this:

INSERT INTO tab1 VALUES(?,?,?); 

Then use the sqlite3_bind_XXXX() functions to bind your large string values to the SQL statement. The use of binding obviates the need to escape quote characters in the string, reducing the risk of SQL injection attacks. It is also runs faster since the large string does not need to be parsed or copied as much.

The maximum length of an SQL statement can be lowered at run-time using the sqlite3_limit(db,SQLITE_LIMIT_SQL_LENGTH,size) interface.

EDIT: 26/10/2022 As Tobias explains in his comment, the linked article now depicts the default max length as follows:

Maximum Length Of An SQL Statement
The maximum number of bytes in the text of an SQL statement is limited to SQLITE_MAX_SQL_LENGTH which defaults to 1,000,000,000.

Android Room query limit optional

Now that I'm trying the function:

@Query("SELECT * FROM user LIMIT :limit")
suspend fun getUsers(limit: Int?): List<User>

It is working just the way I want with null parameter. I don't know why it was not working before.

Multi arguments query in sqlite

You can try this.

String selection = "( id=? || id=? || id=? ) && ( status =? || status=? || status=? )";
String[] selectionArgs = new String[]{"1","2",null,"A","B",null};

Or

String selection = "id IN ( ?,?,? ) && status IN (? ,? ,? )";
String[] selectionArgs = new String[]{"1","2",null,"A","B",null};

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