SQLite

** Compute and return a new Expr object which when passed to
** sqlite3ExprCode() will generate all necessary code to compute
** the iField-th column of the vector expression pVector.
**
** The caller owns the returned Expr object and is responsible for
** ensuring that the returned value eventually gets freed.
**
** Ownership of pVector is controlled by the takeOwnership parameter.  If
** takeOwnership is true, this routine takes responsibility for freeing
** pVector, and may do so before returning, hence the caller must not reference
** pVector again.  If takeOwnership is false, then the caller takes
** responsibility for freeing pVector and must ensure the pVector remains
** valid as long as the returned value remains in use.
** The caller retains ownership of pVector and must ensure that pVector
** remains valid as long as the returned value is in use.
*/
Expr *sqlite3ExprForVectorField(
  Parse *pParse,       /* Parsing context */
  Expr *pVector,       /* The vector.  List of expressions or a sub-SELECT */
  int iField,          /* Which column of the vector to return */
  int iField           /* Which column of the vector to return */
  int takeOwnership    /* True to take ownership of pVector before returning */
){
  Expr *pRet;
  assert( sqlite3ExprIsVector(pVector) );
  if( pVector->op==TK_SELECT ){
  /* FIXME: Add support for takeOwnership!=0 */ assert( takeOwnership==0 );
  if( pVector->flags & EP_xIsSelect ){
    assert( pVector->flags & EP_xIsSelect );
    /* The TK_SELECT_COLUMN Expr node:
    **
    ** pLeft:           pVector containing TK_SELECT
    ** pRight:          pVector if ownership taken
    ** iColumn:         Index of a column in pVector
    ** pLeft->iTable:   First in an array of register holding result, or 0
    **                  if the result is not yet computed.
    **
    ** sqlite3ExprDelete() specifically skips the recursive delete of
    ** pLeft on TK_SELECT_COLUMN nodes.  But pRight is followed, so pVector
    ** is included on pRight if ownership is taken.  Typically there will
    ** be multiple TK_SELECT_COLUMN nodes with the same pLeft pointer to 
    ** the pVector, but only one of them will own the pVector.
    */
    pRet = sqlite3PExpr(pParse, TK_SELECT_COLUMN, pVector, 0, 0);
    if( pRet ) pRet->iColumn = iField;
    assert( pRet==0 || pRet->iTable==0 );
  }else{
    if( pVector->op==TK_VECTOR ) pVector = pVector->x.pList->a[iField].pExpr;
    pRet = sqlite3ExprDup(pParse->db, pVector->x.pList->a[iField].pExpr, 0);
    pRet = sqlite3ExprDup(pParse->db, pVector, 0);
  }
  return pRet;
}
#endif /* !define(SQLITE_OMIT_SUBQUERY) */

/*
** If expression pExpr is of type TK_SELECT, generate code to evaluate

no_mem:     
  /* Avoid leaking memory if malloc has failed. */
  sqlite3ExprDelete(db, pExpr);
  sqlite3ExprListDelete(db, pList);
  return 0;
}

/*
** pColumns and pExpr for a vector assignment, like this:
**
**        (a,b,c) = (expr1,expr2,expr3)
** Or:    (a,b,c) = (SELECT x,y,z FROM ....)
**
** For each term of the vector assignment, append new entries to the
** expression list.  In the case of a subquery on the LHS, append
** TK_SELECT_COLUMN expressions.
*/
ExprList *sqlite3ExprListAppendVector(
  Parse *pParse,         /* Parsing context */
  ExprList *pList,       /* List to which to append. Might be NULL */
  IdList *pColumns,      /* List of names of LHS of the assignment */
  Expr *pExpr            /* Vector expression to be appended. Might be NULL */
){
  sqlite3 *db = pParse->db;
  int n;
  int i;
  if( pColumns==0 ) goto vector_append_error;
  if( pExpr==0 ) goto vector_append_error;
  n = sqlite3ExprVectorSize(pExpr);
  if( pColumns->nId!=n ){
    sqlite3ErrorMsg(pParse, "%d columns assigned %d values",
                    pColumns->nId, n);
    goto vector_append_error;
  }
  for(i=0; i<n; i++){
    Expr *pSubExpr = sqlite3ExprForVectorField(pParse, pExpr, i);
    pList = sqlite3ExprListAppend(pParse, pList, pSubExpr);
    if( pList ){
      pList->a[pList->nExpr-1].zName = pColumns->a[i].zName;
      pColumns->a[i].zName = 0;
    }
  }
  if( pExpr->op==TK_SELECT ){
    if( pList && pList->a[0].pExpr ){
      assert( pList->a[0].pExpr->op==TK_SELECT_COLUMN );
      pList->a[0].pExpr->pRight = pExpr;
      pExpr = 0;
    }
  }

vector_append_error:
  sqlite3ExprDelete(db, pExpr);
  sqlite3IdListDelete(db, pColumns);
  return pList;
}

/*
** Set the sort order for the last element on the given ExprList.
*/
void sqlite3ExprListSetSortOrder(ExprList *p, int iSortOrder){
  if( p==0 ) return;
  assert( SQLITE_SO_UNDEFINED<0 && SQLITE_SO_ASC>=0 && SQLITE_SO_DESC>0 );

%type setlist {ExprList*}
%destructor setlist {sqlite3ExprListDelete(pParse->db, $$);}

setlist(A) ::= setlist(A) COMMA nm(X) EQ expr(Y). {
  A = sqlite3ExprListAppend(pParse, A, Y.pExpr);
  sqlite3ExprListSetName(pParse, A, &X, 1);
}
setlist(A) ::= setlist(A) COMMA LP idlist(X) RP EQ expr(Y). {
  A = sqlite3ExprListAppendVector(pParse, A, X, Y.pExpr);
}
setlist(A) ::= nm(X) EQ expr(Y). {
  A = sqlite3ExprListAppend(pParse, 0, Y.pExpr);
  sqlite3ExprListSetName(pParse, A, &X, 1);
}
setlist(A) ::= LP idlist(X) RP EQ expr(Y). {
  A = sqlite3ExprListAppendVector(pParse, 0, X, Y.pExpr);
}

////////////////////////// The INSERT command /////////////////////////////////
//
cmd ::= with(W) insert_cmd(R) INTO fullname(X) idlist_opt(F) select(S). {
  sqlite3WithPush(pParse, W, 1);
  sqlite3Insert(pParse, X, S, F, R);
}

Expr *sqlite3PExpr(Parse*, int, Expr*, Expr*, const Token*);
void sqlite3PExprAddSelect(Parse*, Expr*, Select*);
Expr *sqlite3ExprAnd(sqlite3*,Expr*, Expr*);
Expr *sqlite3ExprFunction(Parse*,ExprList*, Token*);
void sqlite3ExprAssignVarNumber(Parse*, Expr*);
void sqlite3ExprDelete(sqlite3*, Expr*);
ExprList *sqlite3ExprListAppend(Parse*,ExprList*,Expr*);
ExprList *sqlite3ExprListAppendVector(Parse*,ExprList*,IdList*,Expr*);
void sqlite3ExprListSetSortOrder(ExprList*,int);
void sqlite3ExprListSetName(Parse*,ExprList*,Token*,int);
void sqlite3ExprListSetSpan(Parse*,ExprList*,ExprSpan*);
void sqlite3ExprListDelete(sqlite3*, ExprList*);
u32 sqlite3ExprListFlags(const ExprList*);
int sqlite3Init(sqlite3*, char**);
int sqlite3InitCallback(void*, int, char**, char**);

#if defined(SQLITE_ENABLE_DBSTAT_VTAB) || defined(SQLITE_TEST)
int sqlite3DbstatRegister(sqlite3*);
#endif

int sqlite3ExprVectorSize(Expr *pExpr);
int sqlite3ExprIsVector(Expr *pExpr);
Expr *sqlite3VectorFieldSubexpr(Expr*, int);
Expr *sqlite3ExprForVectorField(Parse*,Expr*,int,int);
Expr *sqlite3ExprForVectorField(Parse*,Expr*,int);

#endif /* SQLITEINT_H */

  )){
    int nLeft = sqlite3ExprVectorSize(pExpr->pLeft);
    if( nLeft==sqlite3ExprVectorSize(pExpr->pRight) ){
      int i;
      for(i=0; i<sqlite3ExprVectorSize(pExpr->pLeft); i++){
        int idxNew;
        Expr *pNew;
        Expr *pLeft = sqlite3ExprForVectorField(pParse, pExpr->pLeft, i, 0);
        Expr *pRight = sqlite3ExprForVectorField(pParse, pExpr->pRight, i, 0);
        Expr *pLeft = sqlite3ExprForVectorField(pParse, pExpr->pLeft, i);
        Expr *pRight = sqlite3ExprForVectorField(pParse, pExpr->pRight, i);

        pNew = sqlite3PExpr(pParse, pExpr->op, pLeft, pRight, 0);
        idxNew = whereClauseInsert(pWC, pNew, TERM_DYNAMIC);
        exprAnalyze(pSrc, pWC, idxNew);
        markTermAsChild(pWC, idxNew, idxTerm);
      }
      pTerm = &pWC->a[idxTerm];

# 2016-08-18
#
# 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.
#
#***********************************************************************
# The focus of this file is vector assignments in the SET clause of
# an UPDATE statement.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set ::testprefix rowvalue7

do_execsql_test 1.1 {
  CREATE TABLE t1(a,b,c,d);
  CREATE INDEX t1x ON t1(a,b);
  INSERT INTO t1(a,b,c,d) VALUES(1,2,0,0),(3,4,0,0),(5,6,0,0);
  CREATE TABLE t2(w,x,y,z);
  CREATE INDEX t2x ON t2(w,x);
  INSERT INTO t2(w,x,y,z) VALUES(1,2,11,22),(8,9,88,99),(3,5,33,55),(5,6,55,66);

  SELECT *,'|' FROM t1 ORDER BY a;
} {1 2 0 0 | 3 4 0 0 | 5 6 0 0 |}

do_execsql_test 1.2 {
  UPDATE t1 SET (c,d) = (SELECT y,z FROM t2 WHERE (w,x)=(a,b));
  SELECT *,'|' FROM t1 ORDER BY a;
} {1 2 11 22 | 3 4 {} {} | 5 6 55 66 |}

do_execsql_test 1.3 {
  UPDATE t1 SET (c,d) = (SELECT y,z FROM t2 WHERE w=a);
  SELECT *,'|' FROM t1 ORDER BY a;
} {1 2 11 22 | 3 4 33 55 | 5 6 55 66 |}

do_execsql_test 1.4 {
  UPDATE t1 SET (c) = 99 WHERE a=3;
  SELECT *,'|' FROM t1 ORDER BY a;
} {1 2 11 22 | 3 4 99 55 | 5 6 55 66 |}

do_execsql_test 1.5 {
  UPDATE t1 SET b = 8, (c,d) = (123,456) WHERE a=3;
  SELECT *,'|' FROM t1 ORDER BY a;
} {1 2 11 22 | 3 8 123 456 | 5 6 55 66 |}

do_catchsql_test 2.1 {
  UPDATE t1 SET (c,d) = (SELECT x,y,z FROM t2 WHERE w=a);
} {1 {2 columns assigned 3 values}}

do_catchsql_test 2.2 {
  UPDATE t1 SET (b,c,d) = (SELECT x,y FROM t2 WHERE w=a);
} {1 {3 columns assigned 2 values}}

finish_test