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SQLite training in Houston TX on 2019-11-05 (details)
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Overview
Comment:Improved handling of USING and NATURAL JOIN in 3-way and higher joins. Ticket [3338b3fa19ac4ab]
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SHA1: 551ce407bd77149865423511bd52eba2f404161a
User & Date: drh 2011-10-18 18:10:40
Context
2011-10-18
19:14
Fix an uninitialized variable in OR-clause processing. check-in: 54aecd92 user: drh tags: trunk
18:10
Improved handling of USING and NATURAL JOIN in 3-way and higher joins. Ticket [3338b3fa19ac4ab] check-in: 551ce407 user: drh tags: trunk
12:44
Fix a floating-point exception that can occur when an FTS4 query contains a large number of tokens connected by AND or NEAR operators. check-in: 3126754c user: dan tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/resolve.c.

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  ** allowing it to be repopulated by the memcpy() on the following line.
  */
  ExprSetProperty(pExpr, EP_Static);
  sqlite3ExprDelete(db, pExpr);
  memcpy(pExpr, pDup, sizeof(*pExpr));
  sqlite3DbFree(db, pDup);
}



















/*
** Given the name of a column of the form X.Y.Z or Y.Z or just Z, look up
** that name in the set of source tables in pSrcList and make the pExpr 
** expression node refer back to that source column.  The following changes
** are made to pExpr:
**
................................................................................
          pExpr->iTable = pItem->iCursor;
          pExpr->pTab = pTab;
          pSchema = pTab->pSchema;
          pMatch = pItem;
        }
        for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){
          if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
            IdList *pUsing;







            cnt++;
            pExpr->iTable = pItem->iCursor;
            pExpr->pTab = pTab;
            pMatch = pItem;
            pSchema = pTab->pSchema;
            /* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
            pExpr->iColumn = j==pTab->iPKey ? -1 : (i16)j;
            if( i<pSrcList->nSrc-1 ){
              if( pItem[1].jointype & JT_NATURAL ){
                /* If this match occurred in the left table of a natural join,
                ** then skip the right table to avoid a duplicate match */
                pItem++;
                i++;
              }else if( (pUsing = pItem[1].pUsing)!=0 ){
                /* If this match occurs on a column that is in the USING clause
                ** of a join, skip the search of the right table of the join
                ** to avoid a duplicate match there. */
                int k;
                for(k=0; k<pUsing->nId; k++){
                  if( sqlite3StrICmp(pUsing->a[k].zName, zCol)==0 ){
                    pItem++;
                    i++;
                    break;
                  }
                }
              }
            }
            break;
          }
        }
      }
    }

#ifndef SQLITE_OMIT_TRIGGER







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  ** allowing it to be repopulated by the memcpy() on the following line.
  */
  ExprSetProperty(pExpr, EP_Static);
  sqlite3ExprDelete(db, pExpr);
  memcpy(pExpr, pDup, sizeof(*pExpr));
  sqlite3DbFree(db, pDup);
}


/*
** Return TRUE if the name zCol occurs anywhere in the USING clause.
**
** Return FALSE if the USING clause is NULL or if it does not contain
** zCol.
*/
static int nameInUsingClause(IdList *pUsing, const char *zCol){
  if( pUsing ){
    int k;
    for(k=0; k<pUsing->nId; k++){
      if( sqlite3StrICmp(pUsing->a[k].zName, zCol)==0 ) return 1;
    }
  }
  return 0;
}


/*
** Given the name of a column of the form X.Y.Z or Y.Z or just Z, look up
** that name in the set of source tables in pSrcList and make the pExpr 
** expression node refer back to that source column.  The following changes
** are made to pExpr:
**
................................................................................
          pExpr->iTable = pItem->iCursor;
          pExpr->pTab = pTab;
          pSchema = pTab->pSchema;
          pMatch = pItem;
        }
        for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){
          if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
            /* If there has been exactly one prior match and this match
            ** is for the right-hand table of a NATURAL JOIN or is in a 
            ** USING clause, then skip this match.
            */
            if( cnt==1 ){
              if( pItem->jointype & JT_NATURAL ) continue;
              if( nameInUsingClause(pItem->pUsing, zCol) ) continue;
            }
            cnt++;
            pExpr->iTable = pItem->iCursor;
            pExpr->pTab = pTab;
            pMatch = pItem;
            pSchema = pTab->pSchema;
            /* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
            pExpr->iColumn = j==pTab->iPKey ? -1 : (i16)j;




















            break;
          }
        }
      }
    }

#ifndef SQLITE_OMIT_TRIGGER

Changes to test/where3.test.

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      AND bbb.parent = 4
    ORDER BY bbb.title COLLATE NOCASE ASC;
} {
  0 0 1 {SEARCH TABLE aaa USING INDEX aaa_333 (fk=?) (~10 rows)} 
  0 1 0 {SEARCH TABLE aaa AS bbb USING INTEGER PRIMARY KEY (rowid=?) (~1 rows)} 
  0 0 0 {USE TEMP B-TREE FOR ORDER BY}
}




















































































finish_test








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      AND bbb.parent = 4
    ORDER BY bbb.title COLLATE NOCASE ASC;
} {
  0 0 1 {SEARCH TABLE aaa USING INDEX aaa_333 (fk=?) (~10 rows)} 
  0 1 0 {SEARCH TABLE aaa AS bbb USING INTEGER PRIMARY KEY (rowid=?) (~1 rows)} 
  0 0 0 {USE TEMP B-TREE FOR ORDER BY}
}

# Name resolution with NATURAL JOIN and USING
#
do_test where3-6.setup {
  db eval {
    CREATE TABLE t6w(a, w);
    INSERT INTO t6w VALUES(1, 'w-one');
    INSERT INTO t6w VALUES(2, 'w-two');
    INSERT INTO t6w VALUES(9, 'w-nine');
    CREATE TABLE t6x(a, x);
    INSERT INTO t6x VALUES(1, 'x-one');
    INSERT INTO t6x VALUES(3, 'x-three');
    INSERT INTO t6x VALUES(9, 'x-nine');
    CREATE TABLE t6y(a, y);
    INSERT INTO t6y VALUES(1, 'y-one');
    INSERT INTO t6y VALUES(4, 'y-four');
    INSERT INTO t6y VALUES(9, 'y-nine');
    CREATE TABLE t6z(a, z);
    INSERT INTO t6z VALUES(1, 'z-one');
    INSERT INTO t6z VALUES(5, 'z-five');
    INSERT INTO t6z VALUES(9, 'z-nine');
  }
} {}
set cnt 0
foreach predicate {
   {}
   {ORDER BY a}
   {ORDER BY t6w.a}
   {WHERE a>0}
   {WHERE t6y.a>0}
   {WHERE a>0 ORDER BY a}
} {
  incr cnt
  do_test where3-6.$cnt.1 {
    set sql "SELECT * FROM t6w NATURAL JOIN t6x NATURAL JOIN t6y"
    append sql " NATURAL JOIN t6z "
    append sql $::predicate
    db eval $sql
  } {1 w-one x-one y-one z-one 9 w-nine x-nine y-nine z-nine}
  do_test where3-6.$cnt.2 {
    set sql "SELECT * FROM t6w JOIN t6x USING(a) JOIN t6y USING(a)"
    append sql " JOIN t6z USING(a) "
    append sql $::predicate
    db eval $sql
  } {1 w-one x-one y-one z-one 9 w-nine x-nine y-nine z-nine}
  do_test where3-6.$cnt.3 {
    set sql "SELECT * FROM t6w NATURAL JOIN t6x JOIN t6y USING(a)"
    append sql " JOIN t6z USING(a) "
    append sql $::predicate
    db eval $sql
  } {1 w-one x-one y-one z-one 9 w-nine x-nine y-nine z-nine}
  do_test where3-6.$cnt.4 {
    set sql "SELECT * FROM t6w JOIN t6x USING(a) NATURAL JOIN t6y"
    append sql " JOIN t6z USING(a) "
    append sql $::predicate
    db eval $sql
  } {1 w-one x-one y-one z-one 9 w-nine x-nine y-nine z-nine}
  do_test where3-6.$cnt.5 {
    set sql "SELECT * FROM t6w JOIN t6x USING(a) JOIN t6y USING(a)"
    append sql " NATURAL JOIN t6z "
    append sql $::predicate
    db eval $sql
  } {1 w-one x-one y-one z-one 9 w-nine x-nine y-nine z-nine}
  do_test where3-6.$cnt.6 {
    set sql "SELECT * FROM t6w JOIN t6x USING(a) NATURAL JOIN t6y"
    append sql " NATURAL JOIN t6z "
    append sql $::predicate
    db eval $sql
  } {1 w-one x-one y-one z-one 9 w-nine x-nine y-nine z-nine}
  do_test where3-6.$cnt.7 {
    set sql "SELECT * FROM t6w NATURAL JOIN t6x JOIN t6y USING(a)"
    append sql " NATURAL JOIN t6z "
    append sql $::predicate
    db eval $sql
  } {1 w-one x-one y-one z-one 9 w-nine x-nine y-nine z-nine}
  do_test where3-6.$cnt.8 {
    set sql "SELECT * FROM t6w NATURAL JOIN t6x NATURAL JOIN t6y"
    append sql " JOIN t6z USING(a) "
    append sql $::predicate
    db eval $sql
  } {1 w-one x-one y-one z-one 9 w-nine x-nine y-nine z-nine}
}


finish_test