Hi @gerg.borsodi,
You can use following operator for where conditions :
- eq
 - neq
 - gt
 - gte
 - lt
 - lte
 - inq
 - nin
 - like
 - nlike
 - regexp
 
You can read full schema in here
{
  "type": "object",
  "additionalProperties": {
    "oneOf": [
      {
        "type": "object",
        "title":"Search criteria",
        "properties": {
          "eq": {
            "$ref": "#/definitions/value"
          },
          "neq": {
            "$ref": "#/definitions/value"
          },
          "gt": {
            "$ref": "#/definitions/value"
          },
          "gte": {
            "$ref": "#/definitions/value"
          },
          "lt": {
            "$ref": "#/definitions/value"
          },
          "lte": {
            "$ref": "#/definitions/value"
          },
          "inq": {
            "type": "array",
            "items": {
              "$ref": "#/definitions/value"
            }
          },
          "nin": {
            "type": "array",
            "items": {
              "$ref": "#/definitions/value"
            }
          },
          "like": {
            "$ref": "#/definitions/value"
          },
          "nlike": {
            "$ref": "#/definitions/value"
          },
          "regexp": {
            "$ref": "#/definitions/value"
          }
        }
      },
      {
        "title": "Value",
        "$ref": "#/definitions/value"
      }
    ]
  },
  "ui": {
    "ui:subTitle": "A set of conditions all results must match"
  },
  "definitions": {
    "value": {
      "type": [
        "string",
        "number",
        "boolean",
        "array",
        "null"
      ]
    }
  }
}
For example :
However, we recommend to use RAW Query instead, because it much easier to use for complex query. You can then divide the rows into separated tasks by using transformer “Get branches from a pattern”
These article might help you

