Many hyperlinks are disabled.
Use anonymous login
to enable hyperlinks.
Overview
Comment: | Fix the LIMIT clause so that it applies to the entire query in a compound query. Prior to this change LIMITs on compound queries did not work at all. Ticket #393. (CVS 1058) |
---|---|
Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA1: |
543479e3aed77976a0c689cf40811bf8 |
User & Date: | drh 2003-07-20 01:16:47.000 |
Context
2003-07-22
| ||
00:39 | Make sure temporary file names in windows have a full 15 characters of random text at the end. (CVS 1059) (check-in: 6ccb92b14f user: drh tags: trunk) | |
2003-07-20
| ||
01:16 | Fix the LIMIT clause so that it applies to the entire query in a compound query. Prior to this change LIMITs on compound queries did not work at all. Ticket #393. (CVS 1058) (check-in: 543479e3ae user: drh tags: trunk) | |
2003-07-19
| ||
00:44 | Make sure the min() and max() optimizer works correctly when there is a LIMIT clause. Ticket #396. (CVS 1057) (check-in: c35e507176 user: drh tags: trunk) | |
Changes
Changes to src/expr.c.
︙ | ︙ | |||
8 9 10 11 12 13 14 | ** May you find forgiveness for yourself and forgive others. ** May you share freely, never taking more than you give. ** ************************************************************************* ** This file contains routines used for analyzing expressions and ** for generating VDBE code that evaluates expressions in SQLite. ** | | | 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 | ** May you find forgiveness for yourself and forgive others. ** May you share freely, never taking more than you give. ** ************************************************************************* ** This file contains routines used for analyzing expressions and ** for generating VDBE code that evaluates expressions in SQLite. ** ** $Id: expr.c,v 1.97 2003/07/20 01:16:47 drh Exp $ */ #include "sqliteInt.h" #include <ctype.h> /* ** Construct a new expression node and return a pointer to it. Memory ** for this node is obtained from sqliteMalloc(). The calling function |
︙ | ︙ | |||
231 232 233 234 235 236 237 238 239 240 241 242 243 244 | pNew->pHaving = sqliteExprDup(p->pHaving); pNew->pOrderBy = sqliteExprListDup(p->pOrderBy); pNew->op = p->op; pNew->pPrior = sqliteSelectDup(p->pPrior); pNew->nLimit = p->nLimit; pNew->nOffset = p->nOffset; pNew->zSelect = 0; return pNew; } /* ** Add a new element to the end of an expression list. If pList is ** initially NULL, then create a new expression list. | > > | 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 | pNew->pHaving = sqliteExprDup(p->pHaving); pNew->pOrderBy = sqliteExprListDup(p->pOrderBy); pNew->op = p->op; pNew->pPrior = sqliteSelectDup(p->pPrior); pNew->nLimit = p->nLimit; pNew->nOffset = p->nOffset; pNew->zSelect = 0; pNew->iLimit = -1; pNew->iOffset = -1; return pNew; } /* ** Add a new element to the end of an expression list. If pList is ** initially NULL, then create a new expression list. |
︙ | ︙ |
Changes to src/select.c.
︙ | ︙ | |||
8 9 10 11 12 13 14 | ** May you find forgiveness for yourself and forgive others. ** May you share freely, never taking more than you give. ** ************************************************************************* ** This file contains C code routines that are called by the parser ** to handle SELECT statements in SQLite. ** | | | 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 | ** May you find forgiveness for yourself and forgive others. ** May you share freely, never taking more than you give. ** ************************************************************************* ** This file contains C code routines that are called by the parser ** to handle SELECT statements in SQLite. ** ** $Id: select.c,v 1.145 2003/07/20 01:16:47 drh Exp $ */ #include "sqliteInt.h" /* ** Allocate a new Select structure and return a pointer to that ** structure. |
︙ | ︙ | |||
48 49 50 51 52 53 54 55 56 57 58 59 60 61 | pNew->pGroupBy = pGroupBy; pNew->pHaving = pHaving; pNew->pOrderBy = pOrderBy; pNew->isDistinct = isDistinct; pNew->op = TK_SELECT; pNew->nLimit = nLimit; pNew->nOffset = nOffset; } return pNew; } /* ** Given 1 to 3 identifiers preceeding the JOIN keyword, determine the ** type of join. Return an integer constant that expresses that type | > > | 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 | pNew->pGroupBy = pGroupBy; pNew->pHaving = pHaving; pNew->pOrderBy = pOrderBy; pNew->isDistinct = isDistinct; pNew->op = TK_SELECT; pNew->nLimit = nLimit; pNew->nOffset = nOffset; pNew->iLimit = -1; pNew->iOffset = -1; } return pNew; } /* ** Given 1 to 3 identifiers preceeding the JOIN keyword, determine the ** type of join. Return an integer constant that expresses that type |
︙ | ︙ | |||
446 447 448 449 450 451 452 | if( v==0 ) return 0; assert( pEList!=0 ); /* If there was a LIMIT clause on the SELECT statement, then do the check ** to see if this row should be output. */ if( pOrderBy==0 ){ | | | | | | 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 | if( v==0 ) return 0; assert( pEList!=0 ); /* If there was a LIMIT clause on the SELECT statement, then do the check ** to see if this row should be output. */ if( pOrderBy==0 ){ if( p->iOffset>=0 ){ int addr = sqliteVdbeCurrentAddr(v); sqliteVdbeAddOp(v, OP_MemIncr, p->iOffset, addr+2); sqliteVdbeAddOp(v, OP_Goto, 0, iContinue); } if( p->iLimit>=0 ){ sqliteVdbeAddOp(v, OP_MemIncr, p->iLimit, iBreak); } } /* Pull the requested columns. */ if( nColumn>0 ){ for(i=0; i<nColumn; i++){ |
︙ | ︙ | |||
616 617 618 619 620 621 622 | int iParm /* Optional parameter associated with eDest */ ){ int end = sqliteVdbeMakeLabel(v); int addr; if( eDest==SRT_Sorter ) return; sqliteVdbeAddOp(v, OP_Sort, 0, 0); addr = sqliteVdbeAddOp(v, OP_SortNext, 0, end); | | | | | | 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 | int iParm /* Optional parameter associated with eDest */ ){ int end = sqliteVdbeMakeLabel(v); int addr; if( eDest==SRT_Sorter ) return; sqliteVdbeAddOp(v, OP_Sort, 0, 0); addr = sqliteVdbeAddOp(v, OP_SortNext, 0, end); if( p->iOffset>=0 ){ sqliteVdbeAddOp(v, OP_MemIncr, p->iOffset, addr+4); sqliteVdbeAddOp(v, OP_Pop, 1, 0); sqliteVdbeAddOp(v, OP_Goto, 0, addr); } if( p->iLimit>=0 ){ sqliteVdbeAddOp(v, OP_MemIncr, p->iLimit, end); } switch( eDest ){ case SRT_Callback: { sqliteVdbeAddOp(v, OP_SortCallback, nColumn, 0); break; } case SRT_Table: |
︙ | ︙ | |||
1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 | if( pE->dataType==SQLITE_SO_NUM ) continue; assert( pE->iColumn>=0 ); if( pEList->nExpr>pE->iColumn ){ pE->dataType = sqliteExprType(pEList->a[pE->iColumn].pExpr); } } } /* ** This routine is called to process a query that is really the union ** or intersection of two or more separate queries. ** ** "p" points to the right-most of the two queries. the query on the ** left is p->pPrior. The left query could also be a compound query | > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 | if( pE->dataType==SQLITE_SO_NUM ) continue; assert( pE->iColumn>=0 ); if( pEList->nExpr>pE->iColumn ){ pE->dataType = sqliteExprType(pEList->a[pE->iColumn].pExpr); } } } /* ** Compute the iLimit and iOffset fields of the SELECT based on the ** nLimit and nOffset fields. nLimit and nOffset hold the integers ** that appear in the original SQL statement after the LIMIT and OFFSET ** keywords. Or that hold -1 and 0 if those keywords are omitted. ** iLimit and iOffset are the integer memory register numbers for ** counters used to compute the limit and offset. If there is no ** limit and/or offset, then iLimit and iOffset are negative. ** ** This routine changes the values if iLimit and iOffset only if ** a limit or offset is defined by nLimit and nOffset. iLimit and ** iOffset should have been preset to appropriate default values ** (usually but not always -1) prior to calling this routine. ** Only if nLimit>=0 or nOffset>0 do the limit registers get ** redefined. The UNION ALL operator uses this property to force ** the reuse of the same limit and offset registers across multiple ** SELECT statements. */ static void computeLimitRegisters(Parse *pParse, Select *p){ /* ** If the comparison is p->nLimit>0 then "LIMIT 0" shows ** all rows. It is the same as no limit. If the comparision is ** p->nLimit>=0 then "LIMIT 0" show no rows at all. ** "LIMIT -1" always shows all rows. There is some ** contraversy about what the correct behavior should be. ** The current implementation interprets "LIMIT 0" to mean ** no rows. */ if( p->nLimit>=0 ){ int iMem = pParse->nMem++; Vdbe *v = sqliteGetVdbe(pParse); if( v==0 ) return; sqliteVdbeAddOp(v, OP_Integer, -p->nLimit, 0); sqliteVdbeAddOp(v, OP_MemStore, iMem, 1); p->iLimit = iMem; } if( p->nOffset>0 ){ int iMem = pParse->nMem++; Vdbe *v = sqliteGetVdbe(pParse); if( v==0 ) return; sqliteVdbeAddOp(v, OP_Integer, -p->nOffset, 0); sqliteVdbeAddOp(v, OP_MemStore, iMem, 1); p->iOffset = iMem; } } /* ** This routine is called to process a query that is really the union ** or intersection of two or more separate queries. ** ** "p" points to the right-most of the two queries. the query on the ** left is p->pPrior. The left query could also be a compound query |
︙ | ︙ | |||
1275 1276 1277 1278 1279 1280 1281 | ** individual selects always group from left to right. */ static int multiSelect(Parse *pParse, Select *p, int eDest, int iParm){ int rc; /* Success code from a subroutine */ Select *pPrior; /* Another SELECT immediately to our left */ Vdbe *v; /* Generate code to this VDBE */ | | | > > > > > > > > > > > > | | 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 | ** individual selects always group from left to right. */ static int multiSelect(Parse *pParse, Select *p, int eDest, int iParm){ int rc; /* Success code from a subroutine */ Select *pPrior; /* Another SELECT immediately to our left */ Vdbe *v; /* Generate code to this VDBE */ /* Make sure there is no ORDER BY or LIMIT clause on prior SELECTs. Only ** the last SELECT in the series may have an ORDER BY or LIMIT. */ if( p==0 || p->pPrior==0 ) return 1; pPrior = p->pPrior; if( pPrior->pOrderBy ){ sqliteErrorMsg(pParse,"ORDER BY clause should come after %s not before", selectOpName(p->op)); return 1; } if( pPrior->nLimit>=0 || pPrior->nOffset>0 ){ sqliteErrorMsg(pParse,"LIMIT clause should come after %s not before", selectOpName(p->op)); return 1; } /* Make sure we have a valid query engine. If not, create a new one. */ v = sqliteGetVdbe(pParse); if( v==0 ) return 1; /* Create the destination temporary table if necessary */ if( eDest==SRT_TempTable ){ sqliteVdbeAddOp(v, OP_OpenTemp, iParm, 0); eDest = SRT_Table; } /* Generate code for the left and right SELECT statements. */ switch( p->op ){ case TK_ALL: { if( p->pOrderBy==0 ){ pPrior->nLimit = p->nLimit; pPrior->nOffset = p->nOffset; rc = sqliteSelect(pParse, pPrior, eDest, iParm, 0, 0, 0); if( rc ) return rc; p->pPrior = 0; p->iLimit = pPrior->iLimit; p->iOffset = pPrior->iOffset; p->nLimit = -1; p->nOffset = 0; rc = sqliteSelect(pParse, p, eDest, iParm, 0, 0, 0); p->pPrior = pPrior; if( rc ) return rc; break; } /* For UNION ALL ... ORDER BY fall through to the next case */ } case TK_EXCEPT: case TK_UNION: { int unionTab; /* Cursor number of the temporary table holding result */ int op; /* One of the SRT_ operations to apply to self */ int priorOp; /* The SRT_ operation to apply to prior selects */ int nLimit, nOffset; /* Saved values of p->nLimit and p->nOffset */ ExprList *pOrderBy; /* The ORDER BY clause for the right SELECT */ priorOp = p->op==TK_ALL ? SRT_Table : SRT_Union; if( eDest==priorOp && p->pOrderBy==0 && p->nLimit<0 && p->nOffset==0 ){ /* We can reuse a temporary table generated by a SELECT to our ** right. */ unionTab = iParm; }else{ /* We will need to create our own temporary table to hold the ** intermediate results. |
︙ | ︙ | |||
1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 | case TK_EXCEPT: op = SRT_Except; break; case TK_UNION: op = SRT_Union; break; case TK_ALL: op = SRT_Table; break; } p->pPrior = 0; pOrderBy = p->pOrderBy; p->pOrderBy = 0; rc = sqliteSelect(pParse, p, op, unionTab, 0, 0, 0); p->pPrior = pPrior; p->pOrderBy = pOrderBy; if( rc ) return rc; /* Convert the data in the temporary table into whatever form ** it is that we currently need. */ if( eDest!=priorOp || unionTab!=iParm ){ int iCont, iBreak, iStart; assert( p->pEList ); if( eDest==SRT_Callback ){ generateColumnNames(pParse, 0, p->pEList); generateColumnTypes(pParse, p->pSrc, p->pEList); } iBreak = sqliteVdbeMakeLabel(v); iCont = sqliteVdbeMakeLabel(v); sqliteVdbeAddOp(v, OP_Rewind, unionTab, iBreak); iStart = sqliteVdbeCurrentAddr(v); multiSelectSortOrder(p, p->pOrderBy); rc = selectInnerLoop(pParse, p, p->pEList, unionTab, p->pEList->nExpr, p->pOrderBy, -1, eDest, iParm, iCont, iBreak); if( rc ) return 1; sqliteVdbeResolveLabel(v, iCont); sqliteVdbeAddOp(v, OP_Next, unionTab, iStart); sqliteVdbeResolveLabel(v, iBreak); sqliteVdbeAddOp(v, OP_Close, unionTab, 0); if( p->pOrderBy ){ generateSortTail(p, v, p->pEList->nExpr, eDest, iParm); } } break; } case TK_INTERSECT: { int tab1, tab2; int iCont, iBreak, iStart; /* INTERSECT is different from the others since it requires ** two temporary tables. Hence it has its own case. Begin ** by allocating the tables we will need. */ tab1 = pParse->nTab++; tab2 = pParse->nTab++; | > > > > > > > > | 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 | case TK_EXCEPT: op = SRT_Except; break; case TK_UNION: op = SRT_Union; break; case TK_ALL: op = SRT_Table; break; } p->pPrior = 0; pOrderBy = p->pOrderBy; p->pOrderBy = 0; nLimit = p->nLimit; p->nLimit = -1; nOffset = p->nOffset; p->nOffset = 0; rc = sqliteSelect(pParse, p, op, unionTab, 0, 0, 0); p->pPrior = pPrior; p->pOrderBy = pOrderBy; p->nLimit = nLimit; p->nOffset = nOffset; if( rc ) return rc; /* Convert the data in the temporary table into whatever form ** it is that we currently need. */ if( eDest!=priorOp || unionTab!=iParm ){ int iCont, iBreak, iStart; assert( p->pEList ); if( eDest==SRT_Callback ){ generateColumnNames(pParse, 0, p->pEList); generateColumnTypes(pParse, p->pSrc, p->pEList); } iBreak = sqliteVdbeMakeLabel(v); iCont = sqliteVdbeMakeLabel(v); sqliteVdbeAddOp(v, OP_Rewind, unionTab, iBreak); computeLimitRegisters(pParse, p); iStart = sqliteVdbeCurrentAddr(v); multiSelectSortOrder(p, p->pOrderBy); rc = selectInnerLoop(pParse, p, p->pEList, unionTab, p->pEList->nExpr, p->pOrderBy, -1, eDest, iParm, iCont, iBreak); if( rc ) return 1; sqliteVdbeResolveLabel(v, iCont); sqliteVdbeAddOp(v, OP_Next, unionTab, iStart); sqliteVdbeResolveLabel(v, iBreak); sqliteVdbeAddOp(v, OP_Close, unionTab, 0); if( p->pOrderBy ){ generateSortTail(p, v, p->pEList->nExpr, eDest, iParm); } } break; } case TK_INTERSECT: { int tab1, tab2; int iCont, iBreak, iStart; int nLimit, nOffset; /* INTERSECT is different from the others since it requires ** two temporary tables. Hence it has its own case. Begin ** by allocating the tables we will need. */ tab1 = pParse->nTab++; tab2 = pParse->nTab++; |
︙ | ︙ | |||
1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 | if( rc ) return rc; /* Code the current SELECT into temporary table "tab2" */ sqliteVdbeAddOp(v, OP_OpenTemp, tab2, 1); sqliteVdbeAddOp(v, OP_KeyAsData, tab2, 1); p->pPrior = 0; rc = sqliteSelect(pParse, p, SRT_Union, tab2, 0, 0, 0); p->pPrior = pPrior; if( rc ) return rc; /* Generate code to take the intersection of the two temporary ** tables. */ assert( p->pEList ); if( eDest==SRT_Callback ){ generateColumnNames(pParse, 0, p->pEList); generateColumnTypes(pParse, p->pSrc, p->pEList); } iBreak = sqliteVdbeMakeLabel(v); iCont = sqliteVdbeMakeLabel(v); sqliteVdbeAddOp(v, OP_Rewind, tab1, iBreak); iStart = sqliteVdbeAddOp(v, OP_FullKey, tab1, 0); sqliteVdbeAddOp(v, OP_NotFound, tab2, iCont); multiSelectSortOrder(p, p->pOrderBy); rc = selectInnerLoop(pParse, p, p->pEList, tab1, p->pEList->nExpr, p->pOrderBy, -1, eDest, iParm, iCont, iBreak); if( rc ) return 1; | > > > > > > > | 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 | if( rc ) return rc; /* Code the current SELECT into temporary table "tab2" */ sqliteVdbeAddOp(v, OP_OpenTemp, tab2, 1); sqliteVdbeAddOp(v, OP_KeyAsData, tab2, 1); p->pPrior = 0; nLimit = p->nLimit; p->nLimit = -1; nOffset = p->nOffset; p->nOffset = 0; rc = sqliteSelect(pParse, p, SRT_Union, tab2, 0, 0, 0); p->pPrior = pPrior; p->nLimit = nLimit; p->nOffset = nOffset; if( rc ) return rc; /* Generate code to take the intersection of the two temporary ** tables. */ assert( p->pEList ); if( eDest==SRT_Callback ){ generateColumnNames(pParse, 0, p->pEList); generateColumnTypes(pParse, p->pSrc, p->pEList); } iBreak = sqliteVdbeMakeLabel(v); iCont = sqliteVdbeMakeLabel(v); sqliteVdbeAddOp(v, OP_Rewind, tab1, iBreak); computeLimitRegisters(pParse, p); iStart = sqliteVdbeAddOp(v, OP_FullKey, tab1, 0); sqliteVdbeAddOp(v, OP_NotFound, tab2, iCont); multiSelectSortOrder(p, p->pOrderBy); rc = selectInnerLoop(pParse, p, p->pEList, tab1, p->pEList->nExpr, p->pOrderBy, -1, eDest, iParm, iCont, iBreak); if( rc ) return 1; |
︙ | ︙ | |||
1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 | /* Generating code to find the min or the max. Basically all we have ** to do is find the first or the last entry in the chosen index. If ** the min() or max() is on the INTEGER PRIMARY KEY, then find the first ** or last entry in the main table. */ sqliteCodeVerifySchema(pParse, pTab->iDb); base = p->pSrc->a[0].iCursor; sqliteVdbeAddOp(v, OP_Integer, pTab->iDb, 0); sqliteVdbeAddOp(v, OP_OpenRead, base, pTab->tnum); sqliteVdbeChangeP3(v, -1, pTab->zName, P3_STATIC); cont = sqliteVdbeMakeLabel(v); if( pIdx==0 ){ sqliteVdbeAddOp(v, seekOp, base, 0); }else{ | > | 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 | /* Generating code to find the min or the max. Basically all we have ** to do is find the first or the last entry in the chosen index. If ** the min() or max() is on the INTEGER PRIMARY KEY, then find the first ** or last entry in the main table. */ sqliteCodeVerifySchema(pParse, pTab->iDb); base = p->pSrc->a[0].iCursor; computeLimitRegisters(pParse, p); sqliteVdbeAddOp(v, OP_Integer, pTab->iDb, 0); sqliteVdbeAddOp(v, OP_OpenRead, base, pTab->tnum); sqliteVdbeChangeP3(v, -1, pTab->zName, P3_STATIC); cont = sqliteVdbeMakeLabel(v); if( pIdx==0 ){ sqliteVdbeAddOp(v, seekOp, base, 0); }else{ |
︙ | ︙ | |||
2128 2129 2130 2131 2132 2133 2134 | /* Identify column names if we will be using them in a callback. This ** step is skipped if the output is going to some other destination. */ if( eDest==SRT_Callback ){ generateColumnNames(pParse, pTabList, pEList); } | < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < | 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 | /* Identify column names if we will be using them in a callback. This ** step is skipped if the output is going to some other destination. */ if( eDest==SRT_Callback ){ generateColumnNames(pParse, pTabList, pEList); } /* Check for the special case of a min() or max() function by itself ** in the result set. */ if( simpleMinMaxQuery(pParse, p, eDest, iParm) ){ rc = 0; goto select_end; } |
︙ | ︙ | |||
2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 | */ if( pParent && pParentAgg && flattenSubquery(pParse, pParent, parentTab, *pParentAgg, isAgg) ){ if( isAgg ) *pParentAgg = 1; return rc; } /* Identify column types if we will be using a callback. This ** step is skipped if the output is going to a destination other ** than a callback. ** ** We have to do this separately from the creation of column names ** above because if the pTabList contains views then they will not ** have been resolved and we will not know the column types until | > > > > | 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 | */ if( pParent && pParentAgg && flattenSubquery(pParse, pParent, parentTab, *pParentAgg, isAgg) ){ if( isAgg ) *pParentAgg = 1; return rc; } /* Set the limiter. */ computeLimitRegisters(pParse, p); /* Identify column types if we will be using a callback. This ** step is skipped if the output is going to a destination other ** than a callback. ** ** We have to do this separately from the creation of column names ** above because if the pTabList contains views then they will not ** have been resolved and we will not know the column types until |
︙ | ︙ |
Changes to src/sqliteInt.h.
1 2 3 4 5 6 7 8 9 10 11 12 13 | /* ** 2001 September 15 ** ** 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. ** ************************************************************************* ** Internal interface definitions for SQLite. ** | | | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 | /* ** 2001 September 15 ** ** 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. ** ************************************************************************* ** Internal interface definitions for SQLite. ** ** @(#) $Id: sqliteInt.h,v 1.194 2003/07/20 01:16:47 drh Exp $ */ #include "config.h" #include "sqlite.h" #include "hash.h" #include "vdbe.h" #include "parse.h" #include "btree.h" |
︙ | ︙ | |||
774 775 776 777 778 779 780 | ** nLimit is set to -1 if there is no LIMIT clause. nOffset is set to 0. ** If there is a LIMIT clause, the parser sets nLimit to the value of the ** limit and nOffset to the value of the offset (or 0 if there is not ** offset). But later on, nLimit and nOffset become the memory locations ** in the VDBE that record the limit and offset counters. */ struct Select { | < > > < > | 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 | ** nLimit is set to -1 if there is no LIMIT clause. nOffset is set to 0. ** If there is a LIMIT clause, the parser sets nLimit to the value of the ** limit and nOffset to the value of the offset (or 0 if there is not ** offset). But later on, nLimit and nOffset become the memory locations ** in the VDBE that record the limit and offset counters. */ struct Select { ExprList *pEList; /* The fields of the result */ u8 op; /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */ u8 isDistinct; /* True if the DISTINCT keyword is present */ SrcList *pSrc; /* The FROM clause */ Expr *pWhere; /* The WHERE clause */ ExprList *pGroupBy; /* The GROUP BY clause */ Expr *pHaving; /* The HAVING clause */ ExprList *pOrderBy; /* The ORDER BY clause */ Select *pPrior; /* Prior select in a compound select statement */ int nLimit, nOffset; /* LIMIT and OFFSET values. -1 means not used */ int iLimit, iOffset; /* Memory registers holding LIMIT & OFFSET counters */ char *zSelect; /* Complete text of the SELECT command */ }; /* ** The results of a select can be distributed in several ways. */ #define SRT_Callback 1 /* Invoke a callback with each row of result */ |
︙ | ︙ |
Changes to test/limit.test.
︙ | ︙ | |||
8 9 10 11 12 13 14 | # 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 SELECT statements. # | | | 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 | # 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 SELECT statements. # # $Id: limit.test,v 1.10 2003/07/20 01:16:48 drh Exp $ set testdir [file dirname $argv0] source $testdir/tester.tcl # Build some test data # set fd [open data1.txt w] |
︙ | ︙ | |||
208 209 210 211 212 213 214 215 216 | } } {} do_test limit-6.8 { execsql { SELECT * FROM t6 LIMIT 0 OFFSET 1 } } {} finish_test | > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 | } } {} do_test limit-6.8 { execsql { SELECT * FROM t6 LIMIT 0 OFFSET 1 } } {} # Make sure LIMIT works well with compound SELECT statements. # Ticket #393 # do_test limit-7.1.1 { catchsql { SELECT x FROM t2 LIMIT 5 UNION ALL SELECT a FROM t6; } } {1 {LIMIT clause should come after UNION ALL not before}} do_test limit-7.1.2 { catchsql { SELECT x FROM t2 LIMIT 5 UNION SELECT a FROM t6; } } {1 {LIMIT clause should come after UNION not before}} do_test limit-7.1.3 { catchsql { SELECT x FROM t2 LIMIT 5 EXCEPT SELECT a FROM t6 LIMIT 3; } } {1 {LIMIT clause should come after EXCEPT not before}} do_test limit-7.1.4 { catchsql { SELECT x FROM t2 LIMIT 0,5 INTERSECT SELECT a FROM t6; } } {1 {LIMIT clause should come after INTERSECT not before}} do_test limit-7.2 { execsql { SELECT x FROM t2 UNION ALL SELECT a FROM t6 LIMIT 5; } } {31 30 1 2 3} do_test limit-7.3 { execsql { SELECT x FROM t2 UNION ALL SELECT a FROM t6 LIMIT 3 OFFSET 1; } } {30 1 2} do_test limit-7.4 { execsql { SELECT x FROM t2 UNION ALL SELECT a FROM t6 ORDER BY 1 LIMIT 3 OFFSET 1; } } {2 3 4} do_test limit-7.5 { execsql { SELECT x FROM t2 UNION SELECT x+2 FROM t2 LIMIT 2 OFFSET 1; } } {31 32} do_test limit-7.6 { execsql { SELECT x FROM t2 UNION SELECT x+2 FROM t2 ORDER BY 1 DESC LIMIT 2 OFFSET 1; } } {32 31} do_test limit-7.7 { execsql { SELECT a+9 FROM t6 EXCEPT SELECT y FROM t2 LIMIT 2; } } {11 12} do_test limit-7.8 { execsql { SELECT a+9 FROM t6 EXCEPT SELECT y FROM t2 ORDER BY 1 DESC LIMIT 2; } } {13 12} do_test limit-7.9 { execsql { SELECT a+26 FROM t6 INTERSECT SELECT x FROM t2 LIMIT 1; } } {30} do_test limit-7.10 { execsql { SELECT a+27 FROM t6 INTERSECT SELECT x FROM t2 LIMIT 1; } } {30} do_test limit-7.11 { execsql { SELECT a+27 FROM t6 INTERSECT SELECT x FROM t2 LIMIT 1 OFFSET 1; } } {31} do_test limit-7.12 { execsql { SELECT a+27 FROM t6 INTERSECT SELECT x FROM t2 ORDER BY 1 DESC LIMIT 1 OFFSET 1; } } {30} finish_test |
Changes to www/lang.tcl.
1 2 3 | # # Run this Tcl script to generate the sqlite.html file. # | | | 1 2 3 4 5 6 7 8 9 10 11 | # # Run this Tcl script to generate the sqlite.html file. # set rcsid {$Id: lang.tcl,v 1.65 2003/07/20 01:16:48 drh Exp $} puts {<html> <head> <title>Query Language Understood By SQLite</title> </head> <body bgcolor=white> <h1 align=center> |
︙ | ︙ | |||
1548 1549 1550 1551 1552 1553 1554 | expression must exactly match one of the result columns. Each sort expression may be optionally followed by ASC or DESC to specify the sort order.</p> <p>The LIMIT clause places an upper bound on the number of rows returned in the result. A negative LIMIT indicates no upper bound. The optional OFFSET following LIMIT specifies how many | | > > > > > | 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 | expression must exactly match one of the result columns. Each sort expression may be optionally followed by ASC or DESC to specify the sort order.</p> <p>The LIMIT clause places an upper bound on the number of rows returned in the result. A negative LIMIT indicates no upper bound. The optional OFFSET following LIMIT specifies how many rows to skip at the beginning of the result set. In a compound query, the LIMIT clause may only appear on the final SELECT statement. The limit is applied to the entire query not to the individual SELECT statement to which it is attached. </p> <p>A compound SELECT is formed from two or more simple SELECTs connected by one of the operators UNION, UNION ALL, INTERSECT, or EXCEPT. In a compound SELECT, all the constituent SELECTs must specify the same number of result columns. There may be only a single ORDER BY clause at the end of the compound SELECT. The UNION and UNION ALL operators combine the results of the SELECTs to the right and left into |
︙ | ︙ |