What would the freebase MQL query for this?

Question

I want to find the ceo of IBM. What would be the MQL query for this?

Answer 1

The MQL for this search looks like the following.
This particular instance may be a tat more complicated than necessary because I got it initially produced from a Freebase interactive search and then simply added/improved the filters manually.
I verified it with various company names with relative success, i.e. it works provided that the underlying data is properly codified in Freebase (some companies are missing, for some companies the leadership data is incomplete etc.)
There are a few tricks to this query:

• the company name in u0 fitler needs to match precisely the company name as recorded in Freebase. You could use a contains predicate rather than an equal one, but that could introduce many irrelevant hits. For example you need to use "IBM", "Apple Inc.", "General Motors" rather than common alternatives to these names ("International Business Machines", "Apple", "GM"...")
• the u1 filter, on the leadership role is expressed in a extensive One of predicate because unfortunately the nomenclature for these roles is relatively loose, with duplicates (e.g. could be CEO or Chief Executive Officer) and with the fact that the role of CEO is often coupled with other corporate roles such as Chairman [of the board] and/or President etc. I hand picked this list by first looking up (in Freebase) the instances of Leadership Roles which contained "CEO" or "Chief Executive".
• the u2 filter expresses that the to date should be empty, to select only the person currently in office, as opposed to former CEOs (for which hopefully Freebase recorded the end date of their tenure).

Depending on your application, you may need to test that the query returns one and exactly one record, and adapt accordingly if it doesn't.

Freebase MQL editor is a convenient tool test and edit with this kind of queries.

[
  {
    "from": null,
    "id": null,
    "limit": 20,
    "organization": {
      "id": null,
      "name": null,
      "optional": true
    },
    "person": {
      "id": null,
      "name": null,
      "optional": true
    },
    "role": {
      "id": null,
      "name": null,
      "optional": true
    },
    "s0:type": [
      {
        "id": "/organization/leadership",
        "link": [
          {
            "timestamp": [
              {
                "optional": true,
                "type": "/type/datetime",
                "value": null
              }
            ],
            "type": "/type/link"
          }
        ],
        "type": "/type/type"
      }
    ],
    "sort": "s0:type.link.timestamp.value",
    "title": null,
    "to": null,
    "type": "/organization/leadership",
    "u0:organization": [
      {
        "id": null,
        "name": "IBM",
        "type": "/organization/organization"
      }
    ],
    "u1:role": [
      {
        "id": null,
        "name|=": ["Chief Executive Officer", "President and CEO", "Chairman and CEO", "Interim CEO", "Interim Chief Executive Officer", "Founder and CEO", "Chairman, President and CEO", "Managing Director and CEO", "Executive Vice President and Chief Operating Officer", "Co-Founder, Chairman and Chief Executive Officer"],
        "type": "/organization/role"
      }
    ],
    "u2:to": [
      {
      "value": null,
      "optional": "forbidden"
      }
    ]
  }
]​

Sample return (for "IBM", specifically)

{
  "code":          "/api/status/ok",
  "result": [{
    "from":  "2012-01-01",
    "id":    "/m/09t7b08",
    "organization": {
      "id":   "/en/ibm",
      "name": "IBM"
    },
    "person": {
      "id":   "/en/virginia_m_rometty",
      "name": "Virginia M. Rometty"
    },
    "role": {
      "id":   "/en/chairman_president_and_ceo",
      "name": "Chairman, President and CEO"
    },
    "s0:type": [{
      "id":   "/organization/leadership",
      "link": [{
        "timestamp": [{
          "type":  "/type/datetime",
          "value": "2010-01-23T08:02:57.0006Z"
        }],
        "type": "/type/link"
      }],
      "type": "/type/type"
    }],
    "title": "Chairman, President and CEO",
    "to":    null,
    "type":  "/organization/leadership",
    "u0:organization": [{
      "id":   "/en/ibm",
      "name": "IBM",
      "type": "/organization/organization"
    }],
    "u1:role": [{
      "id":   "/en/chairman_president_and_ceo",
      "type": "/organization/role"
    }],
    "u2:to": []
  }