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Overview
Comment:Fix an SQL syntax error in the comment on the omit-left-join optimization. No changes to code.
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SHA3-256: 86b5e5a20e967af7ac444ff0a40c2e8b93b7e5c505eebf6d3753a341b05503a8
User & Date: drh 2020-01-16 12:25:14
Context
2020-01-16
16:12
Do not allow the constant-propagation optimization to apple to ON/USING clause terms as it does not help and it might cause downstream problems. check-in: 1bc783da user: drh tags: trunk
13:02
Very small performance improvement by ensuring that the argument to sqlite3VdbeFreeCursor() is non-NULL. Hold for the next sprint. Leaf check-in: f8801ffd user: drh tags: close-cursor-faster
12:25
Fix an SQL syntax error in the comment on the omit-left-join optimization. No changes to code. check-in: 86b5e5a2 user: drh tags: trunk
11:51
Clean up the definitions of the TERM_ constants in the code generator. Formatting only - no logic changes. check-in: af06f80a user: drh tags: trunk
Changes
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Changes to src/where.c.

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  **     CREATE TABLE t1(ipk INTEGER PRIMARY KEY, v1);
  **     CREATE TABLE t2(ipk INTEGER PRIMARY KEY, v2);
  **     CREATE TABLE t3(ipk INTEGER PRIMARY KEY, v3);
  **
  ** then table t2 can be omitted from the following:
  **
  **     SELECT v1, v3 FROM t1 
  **       LEFT JOIN t2 USING (t1.ipk=t2.ipk)
  **       LEFT JOIN t3 USING (t1.ipk=t3.ipk)
  **
  ** or from:
  **
  **     SELECT DISTINCT v1, v3 FROM t1 
  **       LEFT JOIN t2
  **       LEFT JOIN t3 USING (t1.ipk=t3.ipk)
  */
  notReady = ~(Bitmask)0;
  if( pWInfo->nLevel>=2
   && pResultSet!=0               /* guarantees condition (1) above */
   && OptimizationEnabled(db, SQLITE_OmitNoopJoin)
  ){
    int i;







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  **     CREATE TABLE t1(ipk INTEGER PRIMARY KEY, v1);
  **     CREATE TABLE t2(ipk INTEGER PRIMARY KEY, v2);
  **     CREATE TABLE t3(ipk INTEGER PRIMARY KEY, v3);
  **
  ** then table t2 can be omitted from the following:
  **
  **     SELECT v1, v3 FROM t1 
  **       LEFT JOIN t2 ON (t1.ipk=t2.ipk)
  **       LEFT JOIN t3 ON (t1.ipk=t3.ipk)
  **
  ** or from:
  **
  **     SELECT DISTINCT v1, v3 FROM t1 
  **       LEFT JOIN t2
  **       LEFT JOIN t3 ON (t1.ipk=t3.ipk)
  */
  notReady = ~(Bitmask)0;
  if( pWInfo->nLevel>=2
   && pResultSet!=0               /* guarantees condition (1) above */
   && OptimizationEnabled(db, SQLITE_OmitNoopJoin)
  ){
    int i;