 [
    {
      "name": "schema_name",
      "type": "varchar",
      "scale": -2147483648,
      "primary": 0,
      "nullable": false
    },
    {
      "name": "table_name",
      "type": "varchar",
      "scale": -2147483648,
      "primary": 1,
      "nullable": false
    },
    {
      "name": "column_name",
      "type": "varchar",
      "scale": -2147483648,
      "primary": 2,
      "nullable": false
    },
    {
      "name": "cm_sketch",
      "type": "varchar",
      "scale": -2147483648,
      "primary": -1,
      "nullable": false
    },
   {
     "name": "null_count",
     "type": "bigint",
     "scale": -2147483648,
     "precision": -1,
     "default": 0,
     "primary": -1,
     "nullable": true
   },
   {
     "name": "total_count",
     "type": "bigint",
     "scale": -2147483648,
     "precision": -1,
     "default": 0,
     "primary": -1,
     "nullable": true
   },
   {
     "name": "index",
     "type": "integer",
     "default": 0,
     "precision": -1,
     "primary": -1,
     "nullable": true
   },
   {
     "name": "update_time",
     "type": "timestamp",
     "scale": -2147483648,
     "primary": -1,
     "nullable": true
   }
 ]
