title: jq select substring from a column
body: <p>I have file test.json containing the following:</p>
  
  <pre><code>{
    "result": [
      {
        "short_description": "The Net Energy Metering (NEM) Customer Application Database is used to track Customer Applications for a Net Energy Metering Interconnection Application. In almost all cases, the driver of these applications is prompted by the customer installing solar panels on the roof or his or her residence. There are numerous steps required in order to process the NEM applications. The Net Energy Metering Database facilitates this process and allows ACME to keep track of the current status of each customer application.",
        "managed_by": "Bill Anderson",
        "u_storm_impact_flag": "",
        "business_criticality": "Medium",
        "u_compliance_flag": "",
        "active": "true",
        "emergency_tier": "Tier 3"
      }
    ]
  }
  </code></pre>
  
  <p>I can successfully do this:</p>
  
  <pre><code>cat test.json|jq -r '.result[].short_description'
  
  The Net Energy Metering (NEM) Customer Application Database is used to track Customer Applications for a Net Energy Metering Interconnection Application. In almost all cases, the driver of these applications is prompted by the customer installing solar panels on the roof or his or her residence. There are numerous steps required in order to process the NEM applications. The Net Energy Metering Database facilitates this process and allows PHI to keep track of the current status of each customer application.
  </code></pre>
  
  <p>However, if I just try to extract the first 250 characters of the "short_description" column i get the following error:</p>
  
  <pre><code>cat test.json|jq -r '.result[0:249].short_description'
  
  jq: error (at &lt;stdin&gt;:13): Cannot index array with string "short_description"
  </code></pre>
  
  <p>Can you please tell me what i'm doing wrong ?</p>
  
  <p>Thanks!</p>