return target;
      }
      /* Otherwise, fall thru into the TK_COLUMN case */
    }
    case TK_COLUMN: {
      int iTab = pExpr->iTable;
      if( ExprHasProperty(pExpr, EP_FixedCol) ){






        return sqlite3ExprCodeTarget(pParse, pExpr->pLeft,target);













      }
      if( iTab<0 ){
        if( pParse->iSelfTab<0 ){
          /* Generating CHECK constraints or inserting into partial index */
          return pExpr->iColumn - pParse->iSelfTab;
        }else{
          /* Coding an expression that is part of an index where column names

        return target;
      }
      /* Otherwise, fall thru into the TK_COLUMN case */
    }
    case TK_COLUMN: {
      int iTab = pExpr->iTable;
      if( ExprHasProperty(pExpr, EP_FixedCol) ){
        /* This COLUMN expression is really a constant due to WHERE clause
        ** constraints, and that constant is coded by the pExpr->pLeft
        ** expresssion.  However, make sure the constant has the correct
        ** datatype by applying the Affinity of the table column to the
        ** constant.
        */
        int iReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft,target);
        int aff = sqlite3TableColumnAffinity(pExpr->pTab, pExpr->iColumn);
        if( aff!=SQLITE_AFF_BLOB ){
          static const char zAff[] = "B\000C\000D\000E";
          assert( SQLITE_AFF_BLOB=='A' );
          assert( SQLITE_AFF_TEXT=='B' );
          if( iReg!=target ){
            sqlite3VdbeAddOp2(v, OP_SCopy, iReg, target);
            iReg = target;
          }
          sqlite3VdbeAddOp4(v, OP_Affinity, iReg, 1, 0,
                            &zAff[(aff-'B')*2], P4_STATIC);
        }
        return iReg;
      }
      if( iTab<0 ){
        if( pParse->iSelfTab<0 ){
          /* Generating CHECK constraints or inserting into partial index */
          return pExpr->iColumn - pParse->iSelfTab;
        }else{
          /* Coding an expression that is part of an index where column names

# If the constants are blindly propagated, as shown in the following
# query, the wrong answer results:
#
do_execsql_test 201 {
  SELECT * FROM c3 WHERE x='abc' AND y='abc' AND z='abc';
} {}













































finish_test

# If the constants are blindly propagated, as shown in the following
# query, the wrong answer results:
#
do_execsql_test 201 {
  SELECT * FROM c3 WHERE x='abc' AND y='abc' AND z='abc';
} {}

# Constant propagation caused an incorrect answer in the following
# query.  (Reported by Bentley system on 2018-08-09.)
#
do_execsql_test 300 {
  CREATE TABLE A(id INTEGER PRIMARY KEY, label TEXT);
  CREATE TABLE B(id INTEGER PRIMARY KEY, label TEXT, Aid INTEGER);
  CREATE TABLE C(
    id INTEGER PRIMARY KEY,
    xx INTEGER NOT NULL,
    yy INTEGER,
    zz INTEGER
  );
  CREATE UNIQUE INDEX x2 ON C(yy);
  CREATE UNIQUE INDEX x4 ON C(yy, zz);
  INSERT INTO A(id) VALUES(1);
  INSERT INTO B(id) VALUES(2);
  INSERT INTO C(id,xx,yy,zz) VALUES(99,50,1,2);
  SELECT 1
    FROM A,
         (SELECT id,xx,yy,zz FROM C) subq,
         B
   WHERE A.id='1'
     AND A.id=subq.yy
     AND B.id=subq.zz;
} {1}  
do_execsql_test 301 {
  SELECT 1
    FROM A,
         (SELECT id,xx,yy,zz FROM C) subq,
         B
   WHERE A.id=1
     AND A.id=subq.yy
     AND B.id=subq.zz;
} {1}  
do_execsql_test 302 {
  SELECT 1
    FROM A,
         (SELECT id,yy,zz FROM C) subq,
         B
   WHERE A.id='1'
     AND A.id=subq.yy
     AND B.id=subq.zz;
} {1}  

finish_test