擅长:python、mysql、java
<p>您可以使用<code>agg</code>而不是调用<code>max</code>方法:</p>
<pre class="lang-py prettyprint-override"><code>from pyspark.sql.functions import max
joined_df.groupBy(temp1.datestamp).agg(max("diff").alias("maxDiff"))
</code></pre>
<p>在Scala中类似</p>
<pre class="lang-scala prettyprint-override"><code>import org.apache.spark.sql.functions.max
joined_df.groupBy($"datestamp").agg(max("diff").alias("maxDiff"))
</code></pre>
<p>或者</p>
<pre class="lang-scala prettyprint-override"><code>joined_df.groupBy($"datestamp").agg(max("diff").as("maxDiff"))
</code></pre>