How to get the latest 100 samples for mysql? thanks

dkpengqiuyang

Greeting, I want to find the latest 100 samples from mysql, so I set a auto increase key number and wish to get the subset with "operator: filter with range",but can not get the max of this attribute, did I miss some operator that can find max and min of attribute value ? thanks.

MartinLiebig

Hey,

 

you can extract the max with a Extract Macro operator and to macro calcs there. Or generate an id and use a normal filter on it.

 

Best,

Martin

dkpengqiuyang

thank you , I get max vlaue I want from extract macro, which name is "maxID", than I found the "operator: filter example range" can not get the value from %{maxID}, but "operator: filter example" can work with %{maxID}, I am confused about this.

MartinLiebig

Hey,

 

have a look at this process, it should do the job.

 

~Martin

 

<?xml version="1.0" encoding="UTF-8"?><process version="7.4.000">
  <context>
    <input/>
    <output/>
    <macros/>
  </context>
  <operator activated="true" class="process" compatibility="7.4.000" expanded="true" name="Process">
    <process expanded="true">
      <operator activated="true" class="generate_data" compatibility="7.4.000" expanded="true" height="68" name="Generate Data" width="90" x="45" y="85">
        <parameter key="number_examples" value="1000"/>
        <description align="center" color="transparent" colored="false" width="126">1000 Data points</description>
      </operator>
      <operator activated="true" class="extract_macro" compatibility="7.4.000" expanded="true" height="68" name="Extract Macro" width="90" x="179" y="85">
        <parameter key="macro" value="maxExa"/>
        <list key="additional_macros"/>
        <description align="center" color="transparent" colored="false" width="126">Get Number of Examples</description>
      </operator>
      <operator activated="true" class="generate_macro" compatibility="7.4.000" expanded="true" height="82" name="Generate Macro" width="90" x="313" y="85">
        <list key="function_descriptions">
          <parameter key="minExa" value="eval(%{maxExa})-99"/>
        </list>
        <description align="center" color="transparent" colored="false" width="126">Get Numer of Examples -99</description>
      </operator>
      <operator activated="true" class="filter_example_range" compatibility="7.4.000" expanded="true" height="82" name="Filter Example Range" width="90" x="447" y="85">
        <parameter key="first_example" value="%{minExa}"/>
        <parameter key="last_example" value="%{maxExa}"/>
      </operator>
      <connect from_op="Generate Data" from_port="output" to_op="Extract Macro" to_port="example set"/>
      <connect from_op="Extract Macro" from_port="example set" to_op="Generate Macro" to_port="through 1"/>
      <connect from_op="Generate Macro" from_port="through 1" to_op="Filter Example Range" to_port="example set input"/>
      <connect from_op="Filter Example Range" from_port="example set output" to_port="result 1"/>
      <portSpacing port="source_input 1" spacing="0"/>
      <portSpacing port="sink_result 1" spacing="0"/>
      <portSpacing port="sink_result 2" spacing="0"/>
    </process>
  </operator>
</process>