Filtering

The where argument can be used in queries to filter results based on some field's values. Multiple filters can be used in the same where clause using the _and or the _or operators and can also be used to filter nested relationships, as the following examples demonstrate.

Equality operators

_eq, _neq

The _eq (equal to) or the _neq (not equal to) operators are compatible with any database type, e.g. Boolean, Text, Integer, Float, Double, Date, etc. The following example uses the _eq operator to filter on the nested relation Person, looking for all patients whose first name equals "Priscilla"

{
  patients(where: { person: { firstName: { _eq: "Priscilla" } } }) {
    person {
      id
      firstName
      lastName
      birthDate
    }
  }
}

The _eq or _neq operators will not return rows with null values. To also return rows with null values, the _isNull_ operator needs to be used along with these joined by the _or operator.

Greater than or less than operators

_gt, _lt, _gte, _lte

The _gt (greater than), _lt (less than), _gte (greater than or equal to), _lte (less than or equal to) operators are compatible with any database type, e.g. Boolean, Text, Integer, Float, Double, Date, etc.

The following example gets all patients whose date of birth is greater than or equal to January 1st 2015.

query docs_patients {
  patients(where: { person: { birthDate: { _gte: "2015-01-01" } } }) {
    person {
      firstName
      lastName
      gender
      birthDate
    }
  }
}

List based search operators

(_in, _nin)

The _in (in a list) and _nin (not in list) operators are used to compare field values to a list of values.

The following example gets all patients whose date of birth is greater than or equal to January 1st 2015.

{
  patients(where: { person: { firstName: { _in: ["Mary"] } } }) {
    person {
      firstName
      lastName
      gender
      birthDate
    }
  }
}

Search filter using text values

_like, _nlike, _ilike, _nilike, _similar, _nsimilar, _regex, _nregex, _iregex, _niregex

_like

Fetches objects (case sensitive) where a text field contains the string, e.g. patients whose first name is contains "irley".

{
  patients(where: { person: { firstName: { _like: "%irley%" } } }) {
    person {
      firstName
      lastName
      gender
      birthDate
    }
  }
}

_nlike

Fetches objects (case sensitive) where a text field does not contains the string, e.g. patients whose first name does not contains "irley".

{
  patients(where: { person: { firstName: { _nlike: "%irley%" } } }) {
    person {
      firstName
      lastName
      birthDate
      gender
    }
  }
}

_ilike

Fetches objects where a text field contains the string, regardless of case, e.g. patients whose first name does not contains "iRLey".

{
  patients(where: { person: { firstName: { _ilike: "%irley%" } } }) {
    person {
      firstName
      lastName
      birthDate
      gender
    }
  }
}

_similar

This is case sensitive. An example - patients whose first name begins with either L, M or O.

{
  patients(where: { person: { firstName: { _similar: "(L|M|O)%" } } }) {
    person {
      firstName
      lastName
      birthDate
      gender
    }
  }
}