SQLite

** pWhere argument is an optional WHERE clause that restricts the
** set of rows in the view that are to be added to the ephemeral table.
*/
void sqlite3MaterializeView(
  Parse *pParse,       /* Parsing context */
  Table *pView,        /* View definition */
  Expr *pWhere,        /* Optional WHERE clause to be added */
  ExprList *pOrderBy,  /* Optional ORDER BY clause */
  Expr *pLimit,        /* Optional LIMIT clause */
  Expr *pOffset,       /* Optional OFFSET clause */
  int iCur             /* Cursor number for ephemeral table */
){
  SelectDest dest;
  Select *pSel;
  SrcList *pFrom;
  sqlite3 *db = pParse->db;
  int iDb = sqlite3SchemaToIndex(db, pView->pSchema);
  pWhere = sqlite3ExprDup(db, pWhere, 0);
  pFrom = sqlite3SrcListAppend(db, 0, 0, 0);
  if( pFrom ){
    assert( pFrom->nSrc==1 );
    pFrom->a[0].zName = sqlite3DbStrDup(db, pView->zName);
    pFrom->a[0].zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zDbSName);
    assert( pFrom->a[0].pOn==0 );
    assert( pFrom->a[0].pUsing==0 );
  }
  pSel = sqlite3SelectNew(pParse, 0, pFrom, pWhere, 0, 0, pOrderBy, 
                          SF_IncludeHidden, pLimit, pOffset);
  sqlite3SelectDestInit(&dest, SRT_EphemTab, iCur);
  sqlite3Select(pParse, pSel, &dest);
  sqlite3SelectDelete(db, pSel);
}
#endif /* !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER) */

#if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY)

  SrcList *pSrc,               /* the FROM clause -- which tables to scan */
  Expr *pWhere,                /* The WHERE clause.  May be null */
  ExprList *pOrderBy,          /* The ORDER BY clause.  May be null */
  Expr *pLimit,                /* The LIMIT clause.  May be null */
  Expr *pOffset,               /* The OFFSET clause.  May be null */
  char *zStmtType              /* Either DELETE or UPDATE.  For err msgs. */
){
  sqlite3 *db = pParse->db;
  Expr *pLhs = NULL;           /* LHS of IN(SELECT...) operator */
  Expr *pInClause = NULL;      /* WHERE rowid IN ( select ) */

  ExprList *pEList = NULL;     /* Expression list contaning only pSelectRowid */
  SrcList *pSelectSrc = NULL;  /* SELECT rowid FROM x ... (dup of pSrc) */
  Select *pSelect = NULL;      /* Complete SELECT tree */
  Table *pTab;

  /* Check that there isn't an ORDER BY without a LIMIT clause.
  */
  if( pOrderBy && pLimit==0 ) {
    sqlite3ErrorMsg(pParse, "ORDER BY without LIMIT on %s", zStmtType);
    sqlite3ExprDelete(pParse->db, pWhere);
    sqlite3ExprListDelete(pParse->db, pOrderBy);
    sqlite3ExprDelete(pParse->db, pLimit);
    sqlite3ExprDelete(pParse->db, pOffset);
    return 0;
  }

  /* We only need to generate a select expression if there
  ** is a limit/offset term to enforce.
  */
  if( pLimit == 0 ) {
    /* if pLimit is null, pOffset will always be null as well. */
    assert( pOffset == 0 );
    return pWhere;
  }

  /* Generate a select expression tree to enforce the limit/offset 
  ** term for the DELETE or UPDATE statement.  For example:
  **   DELETE FROM table_a WHERE col1=1 ORDER BY col2 LIMIT 1 OFFSET 1
  ** becomes:
  **   DELETE FROM table_a WHERE rowid IN ( 
  **     SELECT rowid FROM table_a WHERE col1=1 ORDER BY col2 LIMIT 1 OFFSET 1
  **   );
  */

  pTab = pSrc->a[0].pTab;
  if( HasRowid(pTab) ){
    pLhs = sqlite3PExpr(pParse, TK_ROW, 0, 0);
    pEList = sqlite3ExprListAppend(
        pParse, 0, sqlite3PExpr(pParse, TK_ROW, 0, 0)
    );
  }else{
    Index *pPk = sqlite3PrimaryKeyIndex(pTab);
    if( pPk->nKeyCol==1 ){
      pLhs = sqlite3Expr(db, TK_ID, pTab->aCol[pPk->aiColumn[0]].zName);
    }else{
      int i;
      for(i=0; i<pPk->nKeyCol; i++){
        Expr *p = sqlite3Expr(db, TK_ID, pTab->aCol[pPk->aiColumn[i]].zName);
        pEList = sqlite3ExprListAppend(pParse, pEList, p);
      }
      pLhs = sqlite3PExpr(pParse, TK_VECTOR, 0, 0);
      if( pLhs ){
        pLhs->x.pList = sqlite3ExprListDup(db, pEList, 0);
      }
    }
  }

  /* duplicate the FROM clause as it is needed by both the DELETE/UPDATE tree
  ** and the SELECT subtree. */
  pSrc->a[0].pTab = 0;
  pSelectSrc = sqlite3SrcListDup(pParse->db, pSrc, 0);
  pSrc->a[0].pTab = pTab;




  /* generate the SELECT expression tree. */
  pSelect = sqlite3SelectNew(pParse, pEList, pSelectSrc, pWhere, 0 ,0, 
      pOrderBy,0,pLimit,pOffset

  );

  /* now generate the new WHERE rowid IN clause for the DELETE/UDPATE */
  pInClause = sqlite3PExpr(pParse, TK_IN, pLhs, 0);

  sqlite3PExprAddSelect(pParse, pInClause, pSelect);
  return pInClause;







}
#endif /* defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) */
       /*      && !defined(SQLITE_OMIT_SUBQUERY) */

/*
** Generate code for a DELETE FROM statement.
**
**     DELETE FROM table_wxyz WHERE a<5 AND b NOT NULL;
**                 \________/       \________________/
**                  pTabList              pWhere
*/
void sqlite3DeleteFromLimit(
  Parse *pParse,         /* The parser context */
  SrcList *pTabList,     /* The table from which we should delete things */
  Expr *pWhere,          /* The WHERE clause.  May be null */
  ExprList *pOrderBy,
  Expr *pLimit,
  Expr *pOffset
){
  Vdbe *v;               /* The virtual database engine */
  Table *pTab;           /* The table from which records will be deleted */
  int i;                 /* Loop counter */
  WhereInfo *pWInfo;     /* Information about the WHERE clause */
  Index *pIdx;           /* For looping over indices of the table */
  int iTabCur;           /* Cursor number for the table */

  memset(&sContext, 0, sizeof(sContext));
  db = pParse->db;
  if( pParse->nErr || db->mallocFailed ){
    goto delete_from_cleanup;
  }
  assert( pTabList->nSrc==1 );


  /* Locate the table which we want to delete.  This table has to be
  ** put in an SrcList structure because some of the subroutines we
  ** will be calling are designed to work with multiple tables and expect
  ** an SrcList* parameter instead of just a Table* parameter.
  */
  pTab = sqlite3SrcListLookup(pParse, pTabList);

# define pTrigger 0
# define isView 0
#endif
#ifdef SQLITE_OMIT_VIEW
# undef isView
# define isView 0
#endif

#ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
  if( !isView ){
    pWhere = sqlite3LimitWhere(
        pParse, pTabList, pWhere, pOrderBy, pLimit, pOffset, "DELETE"
    );
    pOrderBy = 0;
    pLimit = pOffset = 0;
  }
#endif

  /* If pTab is really a view, make sure it has been initialized.
  */
  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
    goto delete_from_cleanup;
  }

  sqlite3BeginWriteOperation(pParse, 1, iDb);

  /* If we are trying to delete from a view, realize that view into
  ** an ephemeral table.
  */
#if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
  if( isView ){
    sqlite3MaterializeView(pParse, pTab, 
        pWhere, pOrderBy, pLimit, pOffset, iTabCur
    );
    iDataCur = iIdxCur = iTabCur;
    pOrderBy = 0;
    pLimit = pOffset = 0;
  }
#endif

  /* Resolve the column names in the WHERE clause.
  */
  memset(&sNC, 0, sizeof(sNC));
  sNC.pParse = pParse;

    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows deleted", SQLITE_STATIC);
  }

delete_from_cleanup:
  sqlite3AuthContextPop(&sContext);
  sqlite3SrcListDelete(db, pTabList);
  sqlite3ExprDelete(db, pWhere);
  sqlite3ExprListDelete(db, pOrderBy);
  sqlite3ExprDelete(db, pLimit);
  sqlite3ExprDelete(db, pOffset);
  sqlite3DbFree(db, aToOpen);
  return;
}
/* Make sure "isView" and other macros defined above are undefined. Otherwise
** they may interfere with compilation of other functions in this file
** (or in another file, if this file becomes part of the amalgamation).  */
#ifdef isView

/////////////////////////// The DELETE statement /////////////////////////////
//
%ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
cmd ::= with(C) DELETE FROM fullname(X) indexed_opt(I) where_opt(W) 
        orderby_opt(O) limit_opt(L). {
  sqlite3WithPush(pParse, C, 1);
  sqlite3SrcListIndexedBy(pParse, X, &I);

  sqlite3DeleteFromLimit(pParse,X,W,O,L.pLimit,L.pOffset); 
}
%endif
%ifndef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
cmd ::= with(C) DELETE FROM fullname(X) indexed_opt(I) where_opt(W). {
  sqlite3WithPush(pParse, C, 1);
  sqlite3SrcListIndexedBy(pParse, X, &I);
  sqlite3DeleteFrom(pParse,X,W);

//
%ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
cmd ::= with(C) UPDATE orconf(R) fullname(X) indexed_opt(I) SET setlist(Y)
        where_opt(W) orderby_opt(O) limit_opt(L).  {
  sqlite3WithPush(pParse, C, 1);
  sqlite3SrcListIndexedBy(pParse, X, &I);
  sqlite3ExprListCheckLength(pParse,Y,"set list"); 
#if 0
  W = sqlite3LimitWhere(pParse, X, W, O, L.pLimit, L.pOffset, "UPDATE");
#endif
  sqlite3UpdateLimit(pParse,X,Y,W,R,O,L.pLimit,L.pOffset);
}
%endif
%ifndef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
cmd ::= with(C) UPDATE orconf(R) fullname(X) indexed_opt(I) SET setlist(Y)
        where_opt(W).  {
  sqlite3WithPush(pParse, C, 1);
  sqlite3SrcListIndexedBy(pParse, X, &I);

void sqlite3SelectDelete(sqlite3*, Select*);
Table *sqlite3SrcListLookup(Parse*, SrcList*);
int sqlite3IsReadOnly(Parse*, Table*, int);
void sqlite3OpenTable(Parse*, int iCur, int iDb, Table*, int);
#if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY)
Expr *sqlite3LimitWhere(Parse*,SrcList*,Expr*,ExprList*,Expr*,Expr*,char*);
#endif
void sqlite3DeleteFromLimit(Parse*, SrcList*, Expr*, ExprList*, Expr*, Expr*);
#define sqlite3DeleteFrom(x,y,z) sqlite3DeleteFromLimit(x,y,z,0,0,0)
void sqlite3UpdateLimit(Parse*, SrcList*, ExprList*, Expr*, int,
                        ExprList*,Expr*,Expr*);
#define sqlite3Update(v,w,x,y,z) sqlite3UpdateLimit(v,w,x,y,z,0,0,0)
WhereInfo *sqlite3WhereBegin(Parse*,SrcList*,Expr*,ExprList*,ExprList*,u16,int);
void sqlite3WhereEnd(WhereInfo*);
LogEst sqlite3WhereOutputRowCount(WhereInfo*);
int sqlite3WhereIsDistinct(WhereInfo*);
int sqlite3WhereIsOrdered(WhereInfo*);
int sqlite3WhereOrderedInnerLoop(WhereInfo*);
int sqlite3WhereIsSorted(WhereInfo*);

void sqlite3RegisterDateTimeFunctions(void);
void sqlite3RegisterPerConnectionBuiltinFunctions(sqlite3*);
int sqlite3SafetyCheckOk(sqlite3*);
int sqlite3SafetyCheckSickOrOk(sqlite3*);
void sqlite3ChangeCookie(Parse*, int);

#if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
void sqlite3MaterializeView(Parse*, Table*, Expr*, ExprList*,Expr*,Expr*,int);
#endif

#ifndef SQLITE_OMIT_TRIGGER
  void sqlite3BeginTrigger(Parse*, Token*,Token*,int,int,IdList*,SrcList*,
                           Expr*,int, int);
  void sqlite3FinishTrigger(Parse*, TriggerStep*, Token*);
  void sqlite3DropTrigger(Parse*, SrcList*, int);

/*
** Process an UPDATE statement.
**
**   UPDATE OR IGNORE table_wxyz SET a=b, c=d WHERE e<5 AND f NOT NULL;
**          \_______/ \________/     \______/       \________________/
*            onError   pTabList      pChanges             pWhere
*/
void sqlite3UpdateLimit(
  Parse *pParse,         /* The parser context */
  SrcList *pTabList,     /* The table in which we should change things */
  ExprList *pChanges,    /* Things to be changed */
  Expr *pWhere,          /* The WHERE clause.  May be null */
  int onError,           /* How to handle constraint errors */
  ExprList *pOrderBy,
  Expr *pLimit,
  Expr *pOffset
){
  int i, j;              /* Loop counters */
  Table *pTab;           /* The table to be updated */
  int addrTop = 0;       /* VDBE instruction address of the start of the loop */
  WhereInfo *pWInfo;     /* Information about the WHERE clause */
  Vdbe *v;               /* The virtual database engine */
  Index *pIdx;           /* For looping over indices */

# define isView 0
# define tmask 0
#endif
#ifdef SQLITE_OMIT_VIEW
# undef isView
# define isView 0
#endif

#ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
  if( !isView ){
    pWhere = sqlite3LimitWhere(
        pParse, pTabList, pWhere, pOrderBy, pLimit, pOffset, "UPDATE"
    );
    pOrderBy = 0;
    pLimit = pOffset = 0;
  }
#endif

  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
    goto update_cleanup;
  }
  if( sqlite3IsReadOnly(pParse, pTab, tmask) ){
    goto update_cleanup;
  }

  }

  /* If we are trying to update a view, realize that view into
  ** an ephemeral table.
  */
#if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
  if( isView ){
    sqlite3MaterializeView(pParse, pTab, 
        pWhere, pOrderBy, pLimit, pOffset, iDataCur
    );
    pOrderBy = 0;
    pLimit = pOffset = 0;
  }
#endif

  /* Resolve the column names in all the expressions in the
  ** WHERE clause.
  */
  if( sqlite3ResolveExprNames(&sNC, pWhere) ){

update_cleanup:
  sqlite3AuthContextPop(&sContext);
  sqlite3DbFree(db, aXRef); /* Also frees aRegIdx[] and aToOpen[] */
  sqlite3SrcListDelete(db, pTabList);
  sqlite3ExprListDelete(db, pChanges);
  sqlite3ExprDelete(db, pWhere);
  sqlite3ExprListDelete(db, pOrderBy);
  sqlite3ExprDelete(db, pLimit);
  sqlite3ExprDelete(db, pOffset);
  return;
}
/* Make sure "isView" and other macros defined above are undefined. Otherwise
** they may interfere with compilation of other functions in this file
** (or in another file, if this file becomes part of the amalgamation).  */
#ifdef isView
 #undef isView

    COMMIT;
  }
  return {}
}

ifcapable {update_delete_limit} {

  execsql { CREATE TABLE t1(x, y) }

  # check syntax error support
  do_test wherelimit-0.1 {
    catchsql {DELETE FROM t1 ORDER BY x}
  } {1 {ORDER BY without LIMIT on DELETE}}
  do_test wherelimit-0.2 {
    catchsql {DELETE FROM t1 WHERE x=1 ORDER BY x}
  } {1 {ORDER BY without LIMIT on DELETE}}
  do_test wherelimit-0.3 {
    catchsql {UPDATE t1 SET y=1 WHERE x=1 ORDER BY x}
  } {1 {ORDER BY without LIMIT on UPDATE}}

  execsql { DROP TABLE t1 }

  # no AS on table sources
  do_test wherelimit-0.4 {
    catchsql {DELETE FROM t1 AS a WHERE x=1}
  } {1 {near "AS": syntax error}}
  do_test wherelimit-0.5 {
    catchsql {UPDATE t1 AS a SET y=1 WHERE x=1}

    BEGIN
      DELETE FROM t1 WHERE rowid=old.r;
      DELETE FROM t2 WHERE rowid=old.r;
    END;
  } {}
  do_catchsql_test wherelimit-4.2 {
    DELETE FROM tv WHERE 1 LIMIT 2;
  } {0 {}}
  do_catchsql_test wherelimit-4.3 {
    DELETE FROM tv WHERE 1 ORDER BY a LIMIT 2;
  } {0 {}}
  do_execsql_test wherelimit-4.10 {
    CREATE TABLE t3(a,b,c,d TEXT, PRIMARY KEY(a,b)) WITHOUT ROWID;
    INSERT INTO t3(a,b,c,d) VALUES(1,2,3,4),(5,6,7,8),(9,10,11,12);
  } {}
  do_catchsql_test wherelimit-4.11 {
    DELETE FROM t3 WHERE a=5 LIMIT 2;
  } {0 {}}
  do_execsql_test wherelimit-4.12 {
    SELECT a,b,c,d FROM t3 ORDER BY 1;
  } {1 2 3 4 9 10 11 12}

}

finish_test

# 2008 October 6
#
# 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 LIMIT ... OFFSET ... clause
#  of UPDATE and DELETE statements.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix wherelimit2

ifcapable !update_delete_limit {
  finish_test
  return
}

do_execsql_test 1.0 {
  CREATE TABLE t1(a, b);
  INSERT INTO t1 VALUES(1, 'f');
  INSERT INTO t1 VALUES(2, 'e');
  INSERT INTO t1 VALUES(3, 'd');
  INSERT INTO t1 VALUES(4, 'c');
  INSERT INTO t1 VALUES(5, 'b');
  INSERT INTO t1 VALUES(6, 'a');

  CREATE VIEW v1 AS SELECT a,b FROM t1;
  CREATE TABLE log(op, a);

  CREATE TRIGGER v1del INSTEAD OF DELETE ON v1 BEGIN
    INSERT INTO log VALUES('delete', old.a);
  END;

  CREATE TRIGGER v1upd INSTEAD OF UPDATE ON v1 BEGIN
    INSERT INTO log VALUES('update', old.a);
  END;
}

do_execsql_test 1.1 {
  DELETE FROM v1 ORDER BY a LIMIT 3;
  SELECT * FROM log; DELETE FROM log;
} {
  delete 1 delete 2 delete 3
}
do_execsql_test 1.2 {
  DELETE FROM v1 ORDER BY b LIMIT 3;
  SELECT * FROM log; DELETE FROM log;
} {
  delete 6 delete 5 delete 4
}
do_execsql_test 1.3 {
  UPDATE v1 SET b = 555 ORDER BY a LIMIT 3;
  SELECT * FROM log; DELETE FROM log;
} {
  update 1 update 2 update 3
}
do_execsql_test 1.4 {
  UPDATE v1 SET b = 555 ORDER BY b LIMIT 3;
  SELECT * FROM log; DELETE FROM log;
} {
  update 6 update 5 update 4
}

do_execsql_test 2.0 {
  CREATE TABLE t2(a, b, c, PRIMARY KEY(a, b)) WITHOUT ROWID;
  INSERT INTO t2 VALUES(1, 1, 'h');
  INSERT INTO t2 VALUES(1, 2, 'g');
  INSERT INTO t2 VALUES(2, 1, 'f');
  INSERT INTO t2 VALUES(2, 2, 'e');
  INSERT INTO t2 VALUES(3, 1, 'd');
  INSERT INTO t2 VALUES(3, 2, 'c');
  INSERT INTO t2 VALUES(4, 1, 'b');
  INSERT INTO t2 VALUES(4, 2, 'a');
}

do_execsql_test 2.1 {
  BEGIN;
    DELETE FROM t2 WHERE b=1 ORDER BY c LIMIT 2;
    SELECT c FROM t2 ORDER BY 1;
  ROLLBACK;
} {a c e f g h}

do_execsql_test 2.2 {
  BEGIN;
    UPDATE t2 SET c=NULL ORDER BY a, b DESC LIMIT 3 OFFSET 1;
    SELECT a, b, c FROM t2;
  ROLLBACK;
} {
  1 1 {} 
  1 2 g 
  2 1 {} 
  2 2 {} 
  3 1 d 
  3 2 c 
  4 1 b 
  4 2 a
}



finish_test