Selecting from nested array in JSON using jq gives empty result

Question

I've been racking my brains over this because on its face, the jq statement I'm using should produce the desired result, but using a tool like jqplay to test gives me a blank result....

Here is the JSON I'm using:

{
  "DBInventory":
    {
      "InventoryID": "ABSCBD",
      "Inventory":[
            {
              "Sys1": 
                {
                  "folder":[
                    {
                      "Scripts":
                        {
                          "files": [
                            "FileName1O",
                            "FileName2O"
                            ]
                        }
                        
                    },
                    {
                      "Schemas":
                        {
                          "files": [
                            "FileName1S",
                            "FileName2S"
                            ]
                        }
                                   
                    },
                    {
                      "StoredProcedures":
                        {
                          "files": [
                            "FileName1SP",
                            "FileName2SP",
                            "FileName3SP"
                            ]
                        }
                            
                    },
                    {
                      "Tables":
                        {
                          "files": [
                            "FileName1T",
                            "FileName2T"
                            ]
                        }
                                      
                    }
                    ]
                }
                
           
            },
            {
              "Sys2": 
                {
                  "folder":[
                    {
                      "MaintScripts":
                        {
                          "files": [
                            "FileName1",
                            "FileName2"
                            ]
                        }
                        
                    },
                    {
                      "Schemas":
                        {
                          "files": [
                            "FileName1",
                            "FileName2"
                            ]
                        }
                                 
                    },
                    {
                      "StoredProcedures":
                        {
                          "files": [
                            "FileName1",
                            "FileName2"
                            ]
                        }
                              
                    },
                    {
                      "Tables":
                        {
                          "files": [
                            "FileName1",
                            "FileName2"
                            ]
                        }
                                        
                    },
                    {
                      "ExternalTables":
                        {
                          "files": [
                            "FileName1",
                            "FileName2"
                            ]
                        }
                              
                    }, 
                    {
                      "Scripts":
                        {
                          "files": [
                            "FileName1",
                            "FileName2"
                            ]
                        }
                                       
                    },
                    {
                      "Views":
                        {
                          "files": [
                            "FileName1v",
                            "FileName2v"
                            ]
                        }
                                       
                    }
                    ]
                }
            }
        ]
    }
  
}

I'm trying to select an object only return the filenames in the array under it like so (say I wanted just the files in 'Schemas' for 'Sys1'). The desired output would be:

["Filename1S","Filename2S"]

from this section:

Inventory > Sys1 > folder > Schemas

The jq statement I've been invoking is:

.DBInventory.Inventory[0][] | select(any(.folder[]; .Key == "Schemas")) | .files[]

Any help would be greatly appreciated. I think I'm close, but the whole blank output has thrown me for a loop.

Answer 1

You don't need a select() at all here. Consider:

jq '.DBInventory.Inventory[0][].folder[].Schemas?.files // empty'

Answer 2

The JSON data is not completely regular, so you could specify the path of interest more precisely, or sprinkle some "bailouts" (such as // empty or ? ) into the query, eg:

.DBInventory.Inventory[].Sys1 // empty
| (.folder[].Schemas // empty).files

or simply:

try (.DBInventory.Inventory[].Sys1.folder[].Schemas.files) // empty