SQLite

    if( nExpr==1 && pEList->a[0].pExpr->iColumn<0 ){
      /* The "x IN (SELECT rowid FROM table)" case */
      int iAddr = sqlite3VdbeAddOp0(v, OP_Once);
      VdbeCoverage(v);

      sqlite3OpenTable(pParse, iTab, iDb, pTab, OP_OpenRead);
      eType = IN_INDEX_ROWID;
      ExplainQueryPlan((pParse, 0,
            "USING ROWID SEARCH ON TABLE %s FOR IN-OPERATOR",pTab->zName));
      sqlite3VdbeJumpHere(v, iAddr);
    }else{
      Index *pIdx;                         /* Iterator variable */
      int affinity_ok = 1;
      int i;

      /* Check that the affinity that will be used to perform each 

}

det 8.2.4 "SELECT count(*) FROM t1" {
  QUERY PLAN
  `--SCAN TABLE t1
}

# 2018-08-16:  While working on Fossil I discovered that EXPLAIN QUERY PLAN
# did not describe IN operators implemented using a ROWID lookup.  These
# test cases ensure that problem as been fixed.
#
do_execsql_test 9.0 {
  -- Schema from Fossil 2018-08-16
  CREATE TABLE forumpost(
    fpid INTEGER PRIMARY KEY,
    froot INT,
    fprev INT,
    firt INT,
    fmtime REAL
  );
  CREATE INDEX forumthread ON forumpost(froot,fmtime);
  CREATE TABLE blob(
    rid INTEGER PRIMARY KEY,
    rcvid INTEGER,
    size INTEGER,
    uuid TEXT UNIQUE NOT NULL,
    content BLOB,
    CHECK( length(uuid)>=40 AND rid>0 )
  );
  CREATE TABLE event(
    type TEXT,
    mtime DATETIME,
    objid INTEGER PRIMARY KEY,
    tagid INTEGER,
    uid INTEGER REFERENCES user,
    bgcolor TEXT,
    euser TEXT,
    user TEXT,
    ecomment TEXT,
    comment TEXT,
    brief TEXT,
    omtime DATETIME
  );
  CREATE INDEX event_i1 ON event(mtime);
  CREATE TABLE private(rid INTEGER PRIMARY KEY);
}
do_eqp_test 9.1 {
  WITH thread(age,duration,cnt,root,last) AS (
    SELECT
      julianday('now') - max(fmtime) AS age,
      max(fmtime) - min(fmtime) AS duration,
      sum(fprev IS NULL) AS msg_count,
      froot,
      (SELECT fpid FROM forumpost
        WHERE froot=x.froot
          AND fpid NOT IN private
        ORDER BY fmtime DESC LIMIT 1)
    FROM forumpost AS x
    WHERE fpid NOT IN private  --- Ensure this table mentioned in EQP output!
    GROUP BY froot
    ORDER BY 1 LIMIT 26 OFFSET 5
  )
  SELECT
    thread.age,
    thread.duration,
    thread.cnt,
    blob.uuid,
    substr(event.comment,instr(event.comment,':')+1)
  FROM thread, blob, event
  WHERE blob.rid=thread.last
    AND event.objid=thread.last
  ORDER BY 1;
} {
  QUERY PLAN
  |--MATERIALIZE xxxxxx
  |  |--SCAN TABLE forumpost AS x USING INDEX forumthread
  |  |--USING ROWID SEARCH ON TABLE private FOR IN-OPERATOR
  |  |--CORRELATED SCALAR SUBQUERY
  |  |  |--SEARCH TABLE forumpost USING COVERING INDEX forumthread (froot=?)
  |  |  `--USING ROWID SEARCH ON TABLE private FOR IN-OPERATOR
  |  `--USE TEMP B-TREE FOR ORDER BY
  |--SCAN SUBQUERY xxxxxx
  |--SEARCH TABLE blob USING INTEGER PRIMARY KEY (rowid=?)
  |--SEARCH TABLE event USING INTEGER PRIMARY KEY (rowid=?)
  `--USE TEMP B-TREE FOR ORDER BY
}

finish_test