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Where clause in SQLite not working in android :(

开发者 https://www.devze.com 2023-01-26 23:10 出处:网络
I\'m getting an annoying error when trying to query some data in SQLite. Here is my code: Cursor cursor= db.query(TABLE_IMAGES, new String[]{\"_id\"}, \"name\" +\" = \"+compareToThis, null, null, nu

I'm getting an annoying error when trying to query some data in SQLite.

Here is my code:

Cursor cursor= db.query(TABLE_IMAGES, new String[]{"_id"}, "name" +" = "+compareToThis, null, null, null, null);

I'm just returning the cursor as a string.

The error is saying:

no such column: compareToThis: while compiling.....the statement

My question is: why is SQLite setting the compareToThis attribute as a column when it's just a value开发者_运维问答?

How can I fix this?

Thanks in advance.


Cursor cursor= db.query(TABLE_IMAGES, new String[]{"_id"}, "name" +" = ?", new String[]{compareToThis},  null, null, null);

The selection must include placeholder for parameter, and the next argument should be the array of parameters.


The solution by Vladimir works, however if you are like me and wonder why your approach did not work initially when it should have, here is why: It is because it expects an integer unless you used (single or double) quotation marks to indicate that it is a string.

For example, in MySql this would return no results:

SELECT * FROM clients WHERE firstName = Bob; -- This will not work.

However when you surround it with quotations, it will return a result because it identifies Bob as a String literal.

Select * FROM clients WHERE firstName = 'Bob'; -- Single quotes work.
Select * FROM clients WHERE firstName = "Bob"; -- Double quotes as well.

Therefore for it to work, you would have to surround your compareToString with single quotes, as Muhhammad mentioned within the comments.

Cursor cursor= db.query(TABLE_IMAGES, new String[]{"_id"}, "name" +'" = "+compareToThis+"'", null, null, null, null);
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