SQLITE_SCANSTAT_NLOOP,
  SQLITE_SCANSTAT_NVISIT,
  SQLITE_SCANSTAT_EST,
  SQLITE_SCANSTAT_NAME,
  SQLITE_SCANSTAT_EXPLAIN,
  SQLITE_SCANSTAT_SELECTID —
Prepared Statement Scan Status Opcodes
#define SQLITE_SCANSTAT_NLOOP
#define SQLITE_SCANSTAT_NVISIT
#define SQLITE_SCANSTAT_EST
#define SQLITE_SCANSTAT_NAME
#define SQLITE_SCANSTAT_EXPLAIN
#define SQLITE_SCANSTAT_SELECTID
The following constants can be used for the T parameter to the
  sqlite3_stmt_scanstatus(S,X,T,V) interface. Each constant designates a
  different metric for sqlite3_stmt_scanstatus() to return.
When the value returned to V is a string, space to hold that
    string is managed by the prepared statement S and will be automatically
    freed when S is finalized.
  - SQLITE_SCANSTAT_NLOOP
- The sqlite3_int64 variable pointed to by the T parameter will be set to
      the total number of times that the X-th loop has run.
- SQLITE_SCANSTAT_NVISIT
- The sqlite3_int64 variable pointed to by the T parameter will be set to
      the total number of rows examined by all iterations of the X-th loop.
- SQLITE_SCANSTAT_EST
- The "double" variable pointed to by the T parameter will be set
      to the query planner's estimate for the average number of rows output from
      each iteration of the X-th loop. If the query planner's estimates was
      accurate, then this value will approximate the quotient NVISIT/NLOOP and
      the product of this value for all prior loops with the same SELECTID will
      be the NLOOP value for the current loop.
- SQLITE_SCANSTAT_NAME
- The "const char *" variable pointed to by the T parameter will
      be set to a zero-terminated UTF-8 string containing the name of the index
      or table used for the X-th loop.
- SQLITE_SCANSTAT_EXPLAIN
- The "const char *" variable pointed to by the T parameter will
      be set to a zero-terminated UTF-8 string containing the EXPLAIN QUERY PLAN
      description for the X-th loop.
- SQLITE_SCANSTAT_SELECT
- The "int" variable pointed to by the T parameter will be set to
      the "select-id" for the X-th loop. The select-id identifies
      which query or subquery the loop is part of. The main query has a
      select-id of zero. The select-id is the same value as is output in the
      first column of an EXPLAIN QUERY PLAN query.