1. A data output method, comprising: extracting, by a computer, a plurality of second data satisfying respective first conditions on one data among a plurality of conditions, from a plurality of first data, as nodes; extracting, from the nodes, combinations of two nodes satisfying respective second conditions on a relationship between two data among the plurality of conditions; creating a first graph by coupling the two nodes of each of the combinations; detecting, from a group of nodes which are included in the nodes and satisfy the same first condition of the first conditions, one or more nodes which do not satisfy one of the second conditions which at least one node of the group satisfies; creating a second graph by deleting the one or more nodes; determining candidates of data combination in the second graph; and outputting a data combination satisfying the plurality of conditions from the candidates of data combination, wherein a process of deleting a node is repeated until a node which does not satisfy one of the second conditions disappears from the first graph.