Use variable for column name in sql query

Question

I'm searching for a word (variable) that occurs in multiple columns of a table. The search has to return the name of the columns in which the word in found.
I could use a foreach loop to go through each column seperately and know the presence of the word in that particular column when the returned cursor isn't null.
The problem is on how to use two different variables (one for column name and one for the word) in SQL query or rawQuery.

My code is as follows:

String[] columnsList = {"col1","col2","col3"};
String[] wordsList = {"fireman","camper","builder"};
for(String i : wordsList){
   for(String j : columnsList){
      Cursor wordQuery = myDatabaseHandle.rawQuery("Select * from myTableOne WHERE " + j + " = ?",new String[]{i});
      if(!(wordQuery==null)){
       Toast.makeText(this,j+"is success",Toast.LENGTH_SHORT).show();
      }
   }
}

But i'm unable to get the answer. I used a seperate string as:

String queryString = "Select * from myTableOne WHERE " + j ;

and in the query,

Cursor WordQuery = myDatabaseHandle.rawQuery(queryString+" = ?",new String[]{i});

But, it's just toasting the names of all columns.

Phantômaxx · Accepted Answer · 2017-07-29 07:32:48Z

2

Your error is here:

if(!(wordQuery==null)){

The cursor is never null.

It can contain 0 records, though.
You can check its length by using wordQuery.getCount()

Something like:

if((wordQuery.getCount() > 0)){

answered Jul 29, 2017 at 7:32

Phantômaxx

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5 Comments

IntelliJ Amiya Over a year ago

Looks like perfect answer .

Phantômaxx Over a year ago

@IntelliJAmiya Thank you, dear!

Dante Over a year ago

Thank you. But I used query instead of rawQuery and it worked perfectly. I didn't know the cursor couldn't be null.That's a new thing learnt :) I'll change it now.

Phantômaxx Over a year ago

I used query instead of rawQuery It makes no difference.

Phantômaxx Over a year ago

If you found this answer useful, flag it as answered. So you can remove this post from the Unanswered Question Queue.

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