When the result of a subquery is to be stored in a register and that

subquery has an ORDER BY clause and an OFFSET, NULL out the destination
register before starting the ORDER BY so that the register will be set
correctly even if the OFFSET is larger than the number of output rows.
Fix for the problem reported in
[forum:/forumpost/0ec80f12d02acb3f|forum post 0ec80f12d02acb3f].

FossilOrigin-Name: 9282bcde301cee2a5c3c068b5b0b7ce992c155ece894413a6a9a51a81e4133fd

diff --git a/manifest b/manifest
index a57d94552a8342519e61445c45cbe82096c0c57e..d1ea5b07f762599fd471992093fa07188ff4867d 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Make\stool/mctimec.tcl\seffect\smore\sregular\sand\sobvious
-D 2022-01-12T01:42:50.451
+C When\sthe\sresult\sof\sa\ssubquery\sis\sto\sbe\sstored\sin\sa\sregister\sand\sthat\nsubquery\shas\san\sORDER\sBY\sclause\sand\san\sOFFSET,\sNULL\sout\sthe\sdestination\nregister\sbefore\sstarting\sthe\sORDER\sBY\sso\sthat\sthe\sregister\swill\sbe\sset\ncorrectly\seven\sif\sthe\sOFFSET\sis\slarger\sthan\sthe\snumber\sof\soutput\srows.\nFix\sfor\sthe\sproblem\sreported\sin\n[forum:/forumpost/0ec80f12d02acb3f|forum\spost\s0ec80f12d02acb3f].
+D 2022-01-12T20:31:14.514
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -551,7 +551,7 @@ F src/printf.c 975f1f5417f2526365b6e6d7f22332e3e11806dad844701d92846292b654ba9a
 F src/random.c 097dc8b31b8fba5a9aca1697aeb9fd82078ec91be734c16bffda620ced7ab83c
 F src/resolve.c 359bc0e445d427583d2ab6110433a5dc777f64a0ecdf8d24826d8b475233ead9
 F src/rowset.c ba9515a922af32abe1f7d39406b9d35730ed65efab9443dc5702693b60854c92
-F src/select.c 342e096c2737a3ee60753e91de6e6660c7f59cd2988b3e1ab641d38fd885003f
+F src/select.c a4a23a70f0a24a1103ac9698f6be181a6ec7ff6c19e03e8899c43cb6d2af09d6
 F src/shell.c.in f5111900d646a07da18e6438d57be20f112397daba6bfc85b117a0da586e55da
 F src/sqlite.h.in a5e0d6bd47e67aabf1475986d36bdcc7bfa9e06566790ebf8e3aa7fa551c9f99
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
@@ -1441,7 +1441,7 @@ F test/stmtvtab1.test 6873dfb24f8e79cbb5b799b95c2e4349060eb7a3b811982749a84b3594
 F test/strict1.test a3ec495471f24c1a6e1a1664bd23e24ccdb27ae93b1a763ee1942ec955b68e71
 F test/strict2.test b22c7a98b5000aef937f1990776497f0e979b1a23bc4f63e2d53b00e59b20070
 F test/subjournal.test 8d4e2572c0ee9a15549f0d8e40863161295107e52f07a3e8012a2e1fdd093c49
-F test/subquery.test d7268d193dd33d5505df965399d3a594e76ae13f
+F test/subquery.test e6fb2ad0a7e5a58cd1619b3e8354484195d6b4473f1cb60b7d2cbf78f501e951
 F test/subquery2.test 90cf944b9de8204569cf656028391e4af1ccc8c0cc02d4ef38ee3be8de1ffb12
 F test/subselect.test 0966aa8e720224dbd6a5e769a3ec2a723e332303
 F test/substr.test a673e3763e247e9b5e497a6cacbaf3da2bd8ec8921c0677145c109f2e633f36b
@@ -1938,8 +1938,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 8ded3f5b0025eb6cc11669c1208681e592862ce352dfff11173dff68daafad30
-R 99e0bf97f8dc74f258301b85c4857b96
-U larrybr
-Z da4e437349126128425252d5fe5b1489
+P 02aaa10f34ab17e76feb7b6f79048309536c0794fcb534b934e06f3daedfeaba
+R 926926c5df28210b2eccf7396e21106e
+U drh
+Z bb0f2b9d8929fd104a37ff3ae2f31816
 # Remove this line to create a well-formed Fossil manifest.

diff --git a/manifest.uuid b/manifest.uuid
index 00e119201fb145bd82d3f33e7aed04db19aea062..2ecb5cbd7f7955774492d5a5bc422671773a60d1 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-02aaa10f34ab17e76feb7b6f79048309536c0794fcb534b934e06f3daedfeaba
\ No newline at end of file
+9282bcde301cee2a5c3c068b5b0b7ce992c155ece894413a6a9a51a81e4133fd
\ No newline at end of file

diff --git a/src/select.c b/src/select.c
index c33903f107ad266624c33127c18c7d5d209f38ac..2d1b54b3aed0304e7518bed2eaabb77c8b53367d 100644 (file)
--- a/src/select.c
+++ b/src/select.c
@@ -1575,6 +1575,9 @@ static void generateSortTail(
 
   iTab = pSort->iECursor;
   if( eDest==SRT_Output || eDest==SRT_Coroutine || eDest==SRT_Mem ){
+    if( eDest==SRT_Mem && p->iOffset ){
+      sqlite3VdbeAddOp2(v, OP_Null, 0, pDest->iSdst);
+    }
     regRowid = 0;
     regRow = pDest->iSdst;
   }else{

diff --git a/test/subquery.test b/test/subquery.test
index 06facbbae05206e72039bf31516ff56cd555592a..e3b4281ede78c72437e9d20d0288033f1da5ec98 100644 (file)
--- a/test/subquery.test
+++ b/test/subquery.test
@@ -594,4 +594,23 @@ do_execsql_test subquery-8.1 {
   SELECT (SELECT 0 FROM (SELECT * FROM (SELECT 0))) AS x WHERE x;
 } {}
 
+# 2022-01-12 https://sqlite.org/forum/forumpost/0ec80f12d02acb3f
+# 
+reset_db
+do_execsql_test subquery-9.1 {
+  CREATE TABLE t1(x);
+  INSERT INTO t1 VALUES(1),(1),(1);
+  SELECT (SELECT DISTINCT x FROM t1 ORDER BY +x LIMIT 1 OFFSET 100) FROM t1;
+} {{} {} {}}
+do_execsql_test subquery-9.2 {
+  SELECT (SELECT DISTINCT x FROM t1 ORDER BY +x LIMIT 1 OFFSET 0) FROM t1;
+} {1 1 1}
+do_execsql_test subquery-9.3 {
+  INSERT INTO t1 VALUES(2);
+  SELECT (SELECT DISTINCT x FROM t1 ORDER BY +x LIMIT 1 OFFSET 1) FROM t1;
+} {2 2 2 2}
+do_execsql_test subquery-9.4 {
+  SELECT (SELECT DISTINCT x FROM t1 ORDER BY +x LIMIT 1 OFFSET 2) FROM t1;
+} {{} {} {} {}}
+
 finish_test