database/sqlite
1
0
Fork 0
mirror of https://github.com/sqlite/sqlite.git synced 2025-11-14 00:22:38 +03:00
Code Activity

:-) (CVS 62)

Browse Source 
FossilOrigin-Name: f4d9089c5d69b16fee5feb49b02e524499e6328d
This commit is contained in:
drh
2000-06-06 21:56:07 +00:00
parent 6b922e545f
commit 82c3d6368d
8 changed files with 387 additions and 176 deletions
Download Patch File Download Diff File Expand all files Collapse all files

254
src/select.c
View File

@@ -24,7 +24,7 @@
** This file contains C code routines that are called by the parser
** to handle SELECT statements.
**
** $Id: select.c,v 1.12 2000/06/06 18:00:16 drh Exp $
** $Id: select.c,v 1.13 2000/06/06 21:56:08 drh Exp $
*/
#include "sqliteInt.h"
@@ -51,6 +51,7 @@ Select *sqliteSelectNew(
pNew->pHaving = pHaving;
pNew->pOrderBy = pOrderBy;
pNew->isDistinct = isDistinct;
pNew->op = TK_SELECT;
return pNew;
}
@@ -58,12 +59,14 @@ Select *sqliteSelectNew(
** Delete the given Select structure and all of its substructures.
*/
void sqliteSelectDelete(Select *p){
if( p==0 ) return;
sqliteExprListDelete(p->pEList);
sqliteIdListDelete(p->pSrc);
sqliteExprDelete(p->pWhere);
sqliteExprListDelete(p->pGroupBy);
sqliteExprDelete(p->pHaving);
sqliteExprListDelete(p->pOrderBy);
sqliteSelectDelete(p->pPrior);
sqliteFree(p);
}
@@ -81,10 +84,16 @@ void sqliteParseInfoReset(Parse *pParse){
/*
** This routine generates the code for the inside of the inner loop
** of a SELECT.
**
** The pEList is used to determine the values for each column in the
** result row. Except if pEList==NULL, then we just read nField
** elements from the srcTab table.
*/
static int selectInnerLoop(
Parse *pParse, /* The parser context */
ExprList *pEList, /* List of values being extracted */
int srcTab, /* Pull data from this table */
int nField, /* Number of fields in the source table */
ExprList *pOrderBy, /* If not NULL, sort results using this key */
int distinct, /* If >=0, make sure results are distinct */
int eDest, /* How to dispose of the results */
@@ -97,8 +106,15 @@ static int selectInnerLoop(
/* Pull the requested fields.
*/
for(i=0; i<pEList->nExpr; i++){
sqliteExprCode(pParse, pEList->a[i].pExpr);
if( pEList ){
for(i=0; i<pEList->nExpr; i++){
sqliteExprCode(pParse, pEList->a[i].pExpr);
}
nField = pEList->nExpr;
}else{
for(i=0; i<nField; i++){
sqliteVdbeAddOp(v, OP_Field, srcTab, i, 0, 0);
}
}
/* If the current result is not distinct, skip the rest
@@ -113,6 +129,7 @@ static int selectInnerLoop(
sqliteVdbeAddOp(v, OP_String, 0, 0, "", lbl);
sqliteVdbeAddOp(v, OP_Put, distinct, 0, 0, 0);
}
/* If there is an ORDER BY clause, then store the results
** in a sorter.
*/
@@ -130,12 +147,22 @@ static int selectInnerLoop(
sqliteVdbeAddOp(v, OP_SortPut, 0, 0, 0, 0);
}else
/* If we are writing to a table, then write the results to the table.
/* In this mode, write each query result to the key of the temporary
** table iParm.
*/
if( eDest==SRT_Table ){
sqliteVdbeAddOp(v, OP_MakeRecord, pEList->nExpr, 0, 0, 0);
sqliteVdbeAddOp(v, OP_New, iParm, 0, 0, 0);
sqliteVdbeAddOp(v, OP_Pull, 1, 0, 0, 0);
if( eDest==SRT_Union ){
sqliteVdbeAddOp(v, OP_MakeRecord, nField, 0, 0, 0);
sqliteVdbeAddOp(v, OP_String, iParm, 0, "", 0);
sqliteVdbeAddOp(v, OP_Put, iParm, 0, 0, 0);
}else
/* Construct a record from the query result, but instead of
** saving that record, use it as a key to delete elements from
** the temporary table iParm.
*/
if( eDest==SRT_Except ){
assert( pEList->nExpr==1 );
sqliteVdbeAddOp(v, OP_String, 0, 0, "", 0);
sqliteVdbeAddOp(v, OP_Put, iParm, 0, 0, 0);
}else
@@ -149,6 +176,7 @@ static int selectInnerLoop(
sqliteVdbeAddOp(v, OP_Put, iParm, 0, 0, 0);
}else
/* If this is a scalar select that is part of an expression, then
** store the results in the appropriate memory cell and break out
** of the scan loop.
@@ -161,7 +189,160 @@ static int selectInnerLoop(
/* If none of the above, send the data to the callback function.
*/
{
sqliteVdbeAddOp(v, OP_Callback, pEList->nExpr, 0, 0, 0);
sqliteVdbeAddOp(v, OP_Callback, nField, 0, 0, 0);
}
return 0;
}
/*
** Generate code that will tell the VDBE how many columns there
** are in the result and the name for each column. This information
** is used to provide "argc" and "azCol[]" values in the callback.
*/
static void generateColumnNames(Vdbe *v, IdList *pTabList, ExprList *pEList){
int i;
sqliteVdbeAddOp(v, OP_ColumnCount, pEList->nExpr, 0, 0, 0);
for(i=0; i<pEList->nExpr; i++){
Expr *p;
if( pEList->a[i].zName ){
char *zName = pEList->a[i].zName;
int addr = sqliteVdbeAddOp(v, OP_ColumnName, i, 0, zName, 0);
if( zName[0]=='\'' || zName[0]=='"' ){
sqliteVdbeDequoteP3(v, addr);
}
continue;
}
p = pEList->a[i].pExpr;
if( p->op!=TK_FIELD || pTabList==0 ){
char zName[30];
sprintf(zName, "field%d", i+1);
sqliteVdbeAddOp(v, OP_ColumnName, i, 0, zName, 0);
}else{
if( pTabList->nId>1 ){
char *zName = 0;
Table *pTab = pTabList->a[p->iTable].pTab;
char *zTab;
zTab = pTabList->a[p->iTable].zAlias;
if( zTab==0 ) zTab = pTab->zName;
sqliteSetString(&zName, zTab, ".", pTab->aCol[p->iField].zName, 0);
sqliteVdbeAddOp(v, OP_ColumnName, i, 0, zName, 0);
sqliteFree(zName);
}else{
Table *pTab = pTabList->a[0].pTab;
char *zName = pTab->aCol[p->iField].zName;
sqliteVdbeAddOp(v, OP_ColumnName, i, 0, zName, 0);
}
}
}
}
/*
** This routine is called to process a query that is really the union
** or intersection of two or more separate queries.
*/
static int multiSelect(Parse *pParse, Select *p, int eDest, int iParm){
int rc;
Select *pPrior;
Vdbe *v;
int i;
/* Make sure we have a valid query engine. If not, create a new one.
*/
v = pParse->pVdbe;
if( v==0 ){
v = pParse->pVdbe = sqliteVdbeCreate(pParse->db->pBe);
}
if( v==0 ){
sqliteSetString(&pParse->zErrMsg, "out of memory", 0);
pParse->nErr++;
return 1;
}
assert( p->pPrior!=0 );
pPrior = p->pPrior;
switch( p->op ){
case TK_ALL: {
rc = sqliteSelect(pParse, pPrior, eDest, iParm);
if( rc ) return rc;
p->pPrior = 0;
rc = sqliteSelect(pParse, p, eDest, iParm);
p->pPrior = pPrior;
break;
}
case TK_EXCEPT:
case TK_UNION: {
int unionTab;
int op;
if( eDest==SRT_Union ){
unionTab = iParm;
}else{
unionTab = pParse->nTab++;
sqliteVdbeAddOp(v, OP_Open, unionTab, 1, 0, 0);
sqliteVdbeAddOp(v, OP_KeyAsData, unionTab, 1, 0, 0);
}
rc = sqliteSelect(pParse, pPrior, SRT_Union, unionTab);
if( rc ) return rc;
op = p->op==TK_EXCEPT ? SRT_Except : SRT_Union;
p->pPrior = 0;
rc = sqliteSelect(pParse, p, op, unionTab);
p->pPrior = pPrior;
if( rc ) return rc;
if( eDest!=SRT_Union ){
int iCont, iBreak;
assert( p->pEList );
generateColumnNames(v, 0, p->pEList);
iBreak = sqliteVdbeMakeLabel(v);
iCont = sqliteVdbeAddOp(v, OP_Next, unionTab, iBreak, 0, 0);
rc = selectInnerLoop(pParse, 0, unionTab, p->pEList->nExpr,
0, -1, eDest, iParm,
iCont, iBreak);
if( rc ) return 1;
sqliteVdbeAddOp(v, OP_Goto, 0, iCont, 0, 0);
sqliteVdbeAddOp(v, OP_Close, unionTab, 0, 0, iBreak);
}
break;
}
case TK_INTERSECT: {
int tab1, tab2;
Select *pPrior;
int iCont, iBreak;
tab1 = pParse->nTab++;
tab2 = pParse->nTab++;
sqliteVdbeAddOp(v, OP_Open, tab1, 1, 0, 0);
sqliteVdbeAddOp(v, OP_KeyAsData, tab1, 1, 0, 0);
rc = sqliteSelect(pParse, pPrior, SRT_Union, tab1);
if( rc ) return rc;
sqliteVdbeAddOp(v, OP_Open, tab2, 1, 0, 0);
sqliteVdbeAddOp(v, OP_KeyAsData, tab2, 1, 0, 0);
p->pPrior = 0;
rc = sqliteSelect(pParse, p, SRT_Union, tab2);
p->pPrior = pPrior;
if( rc ) return rc;
assert( p->pEList );
generateColumnNames(v, 0, p->pEList);
iBreak = sqliteVdbeMakeLabel(v);
iCont = sqliteVdbeAddOp(v, OP_Next, tab1, iBreak, 0, 0);
sqliteVdbeAddOp(v, OP_Key, tab1, 0, 0, 0);
sqliteVdbeAddOp(v, OP_NotFound, tab2, iCont, 0, 0);
rc = selectInnerLoop(pParse, 0, tab1, p->pEList->nExpr,
0, -1, eDest, iParm,
iCont, iBreak);
if( rc ) return 1;
sqliteVdbeAddOp(v, OP_Goto, 0, iCont, 0, 0);
sqliteVdbeAddOp(v, OP_Close, tab2, 0, 0, iBreak);
sqliteVdbeAddOp(v, OP_Close, tab1, 0, 0, 0);
break;
}
}
assert( p->pEList && pPrior->pEList );
if( p->pEList->nExpr!=pPrior->pEList->nExpr ){
sqliteSetString(&pParse->zErrMsg, "SELECTs have different numbers "
"of columns and therefore cannot be joined", 0);
pParse->nErr++;
return 1;
}
return 0;
}
@@ -180,7 +361,9 @@ static int selectInnerLoop(
**
** SRT_Set Store results as keys of a table with cursor iParm
**
** SRT_Table Store results in a regular table with cursor iParm
** SRT_Union Store results as a key in a temporary table iParm
**
** SRT_Except Remove results form the temporary talbe iParm.
**
** This routine returns the number of errors. If any errors are
** encountered, then an appropriate error message is left in
@@ -192,7 +375,7 @@ static int selectInnerLoop(
int sqliteSelect(
Parse *pParse, /* The parser context */
Select *p, /* The SELECT statement being coded. */
int eDest, /* One of SRT_Callback, SRT_Mem, SRT_Set, SRT_Table */
int eDest, /* One of: SRT_Callback Mem Set Union Except */
int iParm /* Save result in this memory location, if >=0 */
){
int i, j;
@@ -208,6 +391,14 @@ int sqliteSelect(
int isDistinct; /* True if the DISTINCT keyword is present */
int distinct; /* Table to use for the distinct set */
/* If there is are a sequence of queries, do the earlier ones first.
*/
if( p->pPrior ){
return multiSelect(pParse, p, eDest, iParm);
}
/* Make local copies of the parameters for this query.
*/
pEList = p->pEList;
pTabList = p->pSrc;
pWhere = p->pWhere;
@@ -255,7 +446,7 @@ int sqliteSelect(
Expr *pExpr = sqliteExpr(TK_FIELD, 0, 0, 0);
pExpr->iTable = i + pParse->nTab;
pExpr->iField = j;
pEList = sqliteExprListAppend(pEList, pExpr, 0);
p->pEList = pEList = sqliteExprListAppend(pEList, pExpr, 0);
}
}
}
@@ -388,40 +579,7 @@ int sqliteSelect(
** step is skipped if the output is going to a table or a memory cell.
*/
if( eDest==SRT_Callback ){
sqliteVdbeAddOp(v, OP_ColumnCount, pEList->nExpr, 0, 0, 0);
for(i=0; i<pEList->nExpr; i++){
Expr *p;
if( pEList->a[i].zName ){
char *zName = pEList->a[i].zName;
int addr = sqliteVdbeAddOp(v, OP_ColumnName, i, 0, zName, 0);
if( zName[0]=='\'' || zName[0]=='"' ){
sqliteVdbeDequoteP3(v, addr);
}
continue;
}
p = pEList->a[i].pExpr;
if( p->op!=TK_FIELD ){
char zName[30];
sprintf(zName, "field%d", i+1);
sqliteVdbeAddOp(v, OP_ColumnName, i, 0, zName, 0);
}else{
if( pTabList->nId>1 ){
char *zName = 0;
Table *pTab = pTabList->a[p->iTable].pTab;
char *zTab;
zTab = pTabList->a[p->iTable].zAlias;
if( zTab==0 ) zTab = pTab->zName;
sqliteSetString(&zName, zTab, ".", pTab->aCol[p->iField].zName, 0);
sqliteVdbeAddOp(v, OP_ColumnName, i, 0, zName, 0);
sqliteFree(zName);
}else{
Table *pTab = pTabList->a[0].pTab;
char *zName = pTab->aCol[p->iField].zName;
sqliteVdbeAddOp(v, OP_ColumnName, i, 0, zName, 0);
}
}
}
generateColumnNames(v, pTabList, pEList);
}
/* Reset the aggregator
@@ -449,7 +607,7 @@ int sqliteSelect(
** aggregates
*/
if( !isAgg ){
if( selectInnerLoop(pParse, pEList, pOrderBy, distinct, eDest, iParm,
if( selectInnerLoop(pParse, pEList, 0, 0, pOrderBy, distinct, eDest, iParm,
pWInfo->iContinue, pWInfo->iBreak) ){
return 1;
}
@@ -528,7 +686,7 @@ int sqliteSelect(
if( pHaving ){
sqliteExprIfFalse(pParse, pHaving, startagg);
}
if( selectInnerLoop(pParse, pEList, pOrderBy, distinct, eDest, iParm,
if( selectInnerLoop(pParse, pEList, 0, 0, pOrderBy, distinct, eDest, iParm,
startagg, endagg) ){
return 1;
}