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SQLite training in Houston TX on 2019-11-05 (details)
Part of the 2019 Tcl Conference

Artifact 3b5ad2c58069e12be2bd86bc5e211a82810521aa:


# 2006 January 31
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the join reordering optimization
# in cases that include a LEFT JOIN.
#
# $Id: where3.test,v 1.2 2006/06/06 11:45:55 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# The following is from ticket #1652.
#
# A comma join then a left outer join:  A,B left join C.
# Arrange indices so that the B table is chosen to go first.
# Also put an index on C, but make sure that A is chosen before C.
#
do_test where3-1.1 {
  execsql {
    CREATE TABLE t1(a, b);
    CREATE TABLE t2(p, q);
    CREATE TABLE t3(x, y);
    
    INSERT INTO t1 VALUES(111,'one');
    INSERT INTO t1 VALUES(222,'two');
    INSERT INTO t1 VALUES(333,'three');
    
    INSERT INTO t2 VALUES(1,111);
    INSERT INTO t2 VALUES(2,222);
    INSERT INTO t2 VALUES(4,444);
    CREATE INDEX t2i1 ON t2(p);
    
    INSERT INTO t3 VALUES(999,'nine');
    CREATE INDEX t3i1 ON t3(x);
    
    SELECT * FROM t1, t2 LEFT JOIN t3 ON q=x WHERE p=2 AND a=q;
  }
} {222 two 2 222 {} {}}

# Ticket #1830
#
# This is similar to the above but with the LEFT JOIN on the
# other side.
#
do_test where3-1.2 {
  execsql {
    CREATE TABLE parent1(parent1key, child1key, Child2key, child3key);
    CREATE TABLE child1 ( child1key NVARCHAR, value NVARCHAR );
    CREATE UNIQUE INDEX PKIDXChild1 ON child1 ( child1key );
    CREATE TABLE child2 ( child2key NVARCHAR, value NVARCHAR );

    INSERT INTO parent1(parent1key,child1key,child2key)
       VALUES ( 1, 'C1.1', 'C2.1' );
    INSERT INTO child1 ( child1key, value ) VALUES ( 'C1.1', 'Value for C1.1' );
    INSERT INTO child2 ( child2key, value ) VALUES ( 'C2.1', 'Value for C2.1' );

    INSERT INTO parent1 ( parent1key, child1key, child2key )
       VALUES ( 2, 'C1.2', 'C2.2' );
    INSERT INTO child2 ( child2key, value ) VALUES ( 'C2.2', 'Value for C2.2' );

    INSERT INTO parent1 ( parent1key, child1key, child2key )
       VALUES ( 3, 'C1.3', 'C2.3' );
    INSERT INTO child1 ( child1key, value ) VALUES ( 'C1.3', 'Value for C1.3' );
    INSERT INTO child2 ( child2key, value ) VALUES ( 'C2.3', 'Value for C2.3' );

    SELECT parent1.parent1key, child1.value, child2.value
    FROM parent1
    LEFT OUTER JOIN child1 ON child1.child1key = parent1.child1key
    INNER JOIN child2 ON child2.child2key = parent1.child2key;
  }
} {1 {Value for C1.1} {Value for C2.1} 2 {} {Value for C2.2} 3 {Value for C1.3} {Value for C2.3}}

finish_test