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Query syntax

Queries to the openFDA API are made up of parameters joined by an ampersand &. Each parameter is followed by an equals sign = and an argument.

Searches have a special syntax: search=field:term. Note that there is only one equals sign = and there is a colon : between the field to search, and the term to search for.

Here are a few syntax patterns that may help if you’re new to this API.

  • search=field:term: Search within a specific field for a term.

  • search=field:term+AND+field:term: Search for records that match both terms.

  • search=field:term+field:term: Search for records that match either of two terms.

  • sort=report_date:desc: Sort records by a specific field in descending order.

  • search=field:term&count=another_field: Search for matching records. Then within that set of records, count the number of times that the unique values of a field appear. Instead of looking at individual records, you can use the count parameter to count how often certain terms (like drug names or patient reactions) appear in the matching set of records.

Here are some example queries that demonstrate how these searches and the count parameter work, all using the drug adverse events endpoint.

Example query

Matching a single search term

This query looks in the drug/event endpoint for a record where one of the reported patient reactions was fatigue.

  1. Search for records where the field patient.reaction.reactionmeddrapt (patient reaction) contains fatigue

Example query

Matching all search terms

This query looks in the drug/event endpoint for a record where both fatigue was a reported patient reaction and the country in which the event happened was Canada. The key here is the +AND+ that joins the two search terms.

  1. Search for records where the field patient.reaction.reactionmeddrapt (patient reaction) contains fatigue and occurcountry (country where the event happened) was ca (the country code for Canada)

Example query

Matching any search terms

This query looks in the drug/event endpoint for a record where either fatigue was a reported patient reaction or the country in which the event happened was Canada.

  1. Search for records where the field patient.reaction.reactionmeddrapt (patient reaction) contains fatigue or occurcountry (country where the event happened) was ca (the country code for Canada)

Example query

Sort in descending order

This query looks in the drug/event endpoint for ten records and sorts them in descending order by received date.

  1. Search for ten records

  2. Sort the results in descending order

  3. Sort by the field receivedate

Example query

Counting records where certain terms occur

This query looks in the drug/event endpoint for all records. It then returns a count of the top patient reactions. For each reaction, the number of records that matched is summed, providing a useful summary.

  1. Search for all records

  2. Count the number of records matching the terms in patient.reaction.reactionmeddrapt.exact. The .exact suffix here tells the API to count whole phrases (e.g. injection site reaction) instead of individual words (e.g. injection, site, and reaction separately)