how can concatenate two string columns in one column in spark python
<p>I want to concatenate two column in dataframe as one column here I want to merge nameFirst and nameLast as column called FULL Name </p>

<pre><code>+---------+---------+--------+
| playerID|nameFirst|nameLast|
+---------+---------+--------+
|aardsda01|    David| Aardsma|
|aaronha01|     Hank|   Aaron|
|aaronto01|   Tommie|   Aaron|
| aasedo01|      Don|    Aase|
+---------+---------+--------+
</code></pre>

<p>I'm trying this code :</p>

<pre><code>sqlContext.sql("SELECT playerID,(nameFirst+nameLast) as full_name FROM Master")
</code></pre>

<p>but it returns </p>

<pre><code>+---------+---------+
| playerID|full_name|
+---------+---------+
|aardsda01|     null|
|aaronha01|     null|
|aaronto01|     null|
| aasedo01|     null|
</code></pre>

<p>any help please </p>