diff --git a/manifest b/manifest
index 320c5bbcb4..f2673bb861 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C When\sdoing\sa\stext-affinity\scomparison\sbetween\stwo\svalues\swhere\sone\sor\sboth\nhave\sboth\sa\stext\sand\sa\snumeric\stype,\smake\ssure\sthe\snumeric\stype\sdoes\snot\nconfuse\sthe\sanswer.\s\sThis\sis\sa\sdeeper\sfix\sto\sthe\sproblem\sobserved\sby\n[forum:/forumpost/3776b48e71|forum\spose\s3776b48e71].\s\sThe\sproblem\sbisects\nto\s[25f2246be404f38b]\son\s2014-08-24,\sprior\sto\sversion\s3.8.7.
-D 2024-01-20T15:13:13.896
+C Allow\s"_"\scharacters\sto\sappear\sfollowing\sany\sdigit\sin\san\sinteger\sor\sreal\sSQL\sliteral.
+D 2024-01-20T16:18:04.854
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -727,7 +727,7 @@ F src/os_win.c 4a50a154aeebc66a1f8fb79c1ff6dd5fe3d005556533361e0d460d41cb6a45a8
 F src/os_win.h 7b073010f1451abe501be30d12f6bc599824944a
 F src/pager.c ff60e98138d2499082ac6230f01ac508aba545315debccfca2fd6042f5f10fcd
 F src/pager.h 4b1140d691860de0be1347474c51fee07d5420bd7f802d38cbab8ea4ab9f538a
-F src/parse.y 020d80386eb216ec9520549106353c517d2bbc89be28752ffdca649a9eaf56ec
+F src/parse.y 2354aaf964e7c4154a9dbe56ea55a797a0fa3021c38b50afe491ea4a387bf971
 F src/pcache.c 040b165f30622a21b7a9a77c6f2e4877a32fb7f22d4c7f0d2a6fa6833a156a75
 F src/pcache.h 1497ce1b823cf00094bb0cf3bac37b345937e6f910890c626b16512316d3abf5
 F src/pcache1.c 602acb23c471bb8d557a6f0083cc2be641d6cafcafa19e481eba7ef4c9ca0f00
@@ -743,7 +743,7 @@ F src/shell.c.in d1ed426aae2d547932971e8019939cacb4dfda8258e45b8924b250e488e2d53
 F src/sqlite.h.in 61a60b4ea04db8ead15e1579b20b64cb56e9f55d52c5f9f9694de630110593a3
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h 3f046c04ea3595d6bfda99b781926b17e672fd6d27da2ba6d8d8fc39981dcb54
-F src/sqliteInt.h 73800d73e21180e6b3df8d0fe7d11758dc24367fd2b0b0075b48fc116de406bb
+F src/sqliteInt.h 6e5e330d84b4ace70e3163721601f01df84566e6db21e1fc45bd00636e3d6640
 F src/sqliteLimit.h 6878ab64bdeb8c24a1d762d45635e34b96da21132179023338c93f820eee6728
 F src/status.c cb11f8589a6912af2da3bb1ec509a94dd8ef27df4d4c1a97e0bcf2309ece972b
 F src/table.c 0f141b58a16de7e2fbe81c308379e7279f4c6b50eb08efeec5892794a0ba30d1
@@ -800,13 +800,13 @@ F src/test_windirent.h da2e5b73c32d09905fbdd00f27cd802212a32a58ead882736fe4f5eb7
 F src/test_window.c cdae419fdcea5bad6dcd9368c685abdad6deb59e9fc8b84b153de513d394ba3f
 F src/test_wsd.c 41cadfd9d97fe8e3e4e44f61a4a8ccd6f7ca8fe9
 F src/threads.c 4ae07fa022a3dc7c5beb373cf744a85d3c5c6c3c
-F src/tokenize.c 23d9f4539880b40226254ad9072f4ecf12eb1902e62aea47aac29928afafcfd5
+F src/tokenize.c b3ab5ee644f3ac54e6a6a856cfb78bdb285e634fae39b38ce0f6e848305ca32e
 F src/treeview.c c6fc972683fd00f975d8b32a81c1f25d2fb7d4035366bf45c9f5622d3ccd70ee
 F src/trigger.c 0905b96b04bb6658509f711a8207287f1315cdbc3df1a1b13ba6483c8e341c81
 F src/update.c 6904814dd62a7a93bbb86d9f1419c7f134a9119582645854ab02b36b676d9f92
 F src/upsert.c fa125a8d3410ce9a97b02cb50f7ae68a2476c405c76aa692d3acf6b8586e9242
 F src/utf.c f23165685a67b4caf8ec08fb274cb3f319103decfb2a980b7cfd55d18dfa855e
-F src/util.c 078f040366d5bd5f47658d045f901c768c1c636c6eaea121f3a1cbd63c3edb5b
+F src/util.c 2b274b03f0d4fd1bf253f160d6b399bc5265338b043c078045c5e32298891ec8
 F src/vacuum.c 604fcdaebe76f3497c855afcbf91b8fa5046b32de3045bab89cc008d68e40104
 F src/vdbe.c 92910d536e0b77505599cd6ae5d9d449e4a5d31ada61da4c0bb84f6ccb2c3189
 F src/vdbe.h 88e19a982df9027ec1c177c793d1a5d34dc23d8f06e3b2d997f43688b05ee0eb
@@ -1355,7 +1355,7 @@ F test/like2.test d3be15fefee3e02fc88942a9b98f26c5339bbdef7783c90023c092c4955fe3
 F test/like3.test a76e5938fadbe6d32807284c796bafd869974a961057bc5fc5a28e06de98745c
 F test/limit.test 350f5d03c29e7dff9a2cde016f84f8d368d40bcd02fa2b2a52fa10c4bf3cbfaf
 F test/limit2.test 9409b033284642a859fafc95f29a5a6a557bd57c1f0d7c3f554bd64ed69df77e
-F test/literal.test 31ef70d425c39b993d0dd61b3f4c65d30b7491e8b3dbbd2d8a23b78b1e8931ca
+F test/literal.test 9bf0ce5ca1034e3c6f83d5dff82abdedcfa1596cd843b2e4f93f58828e123046
 F test/loadext.test faa4f6eed07a5aac35d57fdd7bc07f8fc82464cfd327567c10cf0ba3c86cde04
 F test/loadext2.test 0408380b57adca04004247179837a18e866a74f7
 F test/lock.test be4fe08118fb988fed741f429b7dd5d65e1c90db
@@ -1624,7 +1624,7 @@ F test/speed3.test 694affeb9100526007436334cf7d08f3d74b85ef
 F test/speed4.test abc0ad3399dcf9703abed2fff8705e4f8e416715
 F test/speed4p.explain 6b5f104ebeb34a038b2f714150f51d01143e59aa
 F test/speed4p.test 377a0c48e5a92e0b11c1c5ebb1bc9d83a7312c922bc0cb05970ef5d6a96d1f0c
-F test/speedtest1.c f9505ad6f9c2c3c488a370a2d193e9603a030e51126ef3ecfeb056d21f0e7ad5
+F test/speedtest1.c 19c9b60908d25502d2831f97efee8b81006c356ab8c08327e25d24a4144f2131
 F test/spellfix.test 951a6405d49d1a23d6b78027d3877b4a33eeb8221dcab5704b499755bb4f552e
 F test/spellfix2.test dfc8f519a3fc204cb2dfa8b4f29821ae90f6f8c3
 F test/spellfix3.test 0f9efaaa502a0e0a09848028518a6fb096c8ad33
@@ -2112,7 +2112,7 @@ F tool/showstat4.c 0682ebea7abf4d3657f53c4a243f2e7eab48eab344ed36a94bb75dcd19a5c
 F tool/showwal.c 11eca547980a066b081f512636151233350ac679f29ecf4ebfce7f4530230b3d
 F tool/soak1.tcl 8d407956e1a45b485a8e072470a3e629a27037fe
 F tool/spaceanal.tcl 70c87c04cfd2e77b3e6f21c33ca768296aa8f67d4ab4874786ac8fbb28433477
-F tool/speed-check.sh 72dc85b2c0484af971ee3e7d10775f72b4e771e27e162c2099b3bf25517c25fb
+F tool/speed-check.sh e8d20cc2eb9c85ec1ba562226de144435456dcdff4ee618de49603c6958f6116
 F tool/speedtest.tcl 06c76698485ccf597b9e7dbb1ac70706eb873355
 F tool/speedtest16.c ecb6542862151c3e6509bbc00509b234562ae81e
 F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
@@ -2159,8 +2159,11 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 01868ebcd25fadb2034da234c0636e82d07c5abc902ef66493cadfc988e74d7b
-R c017e3ff6a3cf5fef0c29004a344e6f7
-U drh
-Z f4a73b0af78f34dd85f781f1eb7187c3
+P 709841f88c77276f09701bf38e25503c64b3a0afbe2fbf878136db12f31cbe21
+R 25ab10e7bacd9206b22870bd4ed39a9a
+T *branch * digit-separators
+T *sym-digit-separators *
+T -sym-trunk *
+U dan
+Z ce3fc1dbdae9b70fcb4dc10489ba2fab
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index d23f19cb29..e6ba736181 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-709841f88c77276f09701bf38e25503c64b3a0afbe2fbf878136db12f31cbe21
\ No newline at end of file
+401650aaccbc99246bd4e1ff37a28b78f528178aee2f294d87b9f7fecd7432bb
\ No newline at end of file
diff --git a/src/parse.y b/src/parse.y
index 19491192e3..b0d03a04ee 100644
--- a/src/parse.y
+++ b/src/parse.y
@@ -1923,6 +1923,12 @@ filter_clause(A) ::= FILTER LP WHERE expr(X) RP.  { A = X; }
   SPAN            /* The span operator */
   ERROR           /* An expression containing an error */
 .
+
+term(A) ::= QNUMBER(X). {
+  A=tokenExpr(pParse,@X,X);
+  sqlite3DequoteNumber(A);
+}
+
 /* There must be no more than 255 tokens defined above.  If this grammar
 ** is extended with new rules and tokens, they must either be so few in
 ** number that TK_SPAN is no more than 255, or else the new tokens must
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 79a36e060e..c4aaf9d203 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -609,6 +609,8 @@
 # define SQLITE_OMIT_ALTERTABLE
 #endif
 
+#define SQLITE_DIGIT_SEPARATOR '_'
+
 /*
 ** Return true (non-zero) if the input is an integer that is too large
 ** to fit in 32-bits.  This macro is used inside of various testcase()
@@ -4792,6 +4794,7 @@ int sqlite3ErrorToParser(sqlite3*,int);
 void sqlite3Dequote(char*);
 void sqlite3DequoteExpr(Expr*);
 void sqlite3DequoteToken(Token*);
+void sqlite3DequoteNumber(Expr*);
 void sqlite3TokenInit(Token*,char*);
 int sqlite3KeywordCode(const unsigned char*, int);
 int sqlite3RunParser(Parse*, const char*);
diff --git a/src/tokenize.c b/src/tokenize.c
index f4d013deea..ae1f6da3f1 100644
--- a/src/tokenize.c
+++ b/src/tokenize.c
@@ -441,21 +441,34 @@ int sqlite3GetToken(const unsigned char *z, int *tokenType){
         return i;
       }
 #endif
-      for(i=0; sqlite3Isdigit(z[i]); i++){}
+      for(i=0; 1; i++){
+        if( sqlite3Isdigit(z[i])==0 ){
+          if( z[i]==SQLITE_DIGIT_SEPARATOR ){ *tokenType = TK_QNUMBER; }
+          else{ break; }
+        }
+      }
 #ifndef SQLITE_OMIT_FLOATING_POINT
       if( z[i]=='.' ){
-        i++;
-        while( sqlite3Isdigit(z[i]) ){ i++; }
-        *tokenType = TK_FLOAT;
+        if( *tokenType==TK_INTEGER ) *tokenType = TK_FLOAT;
+        for(i++; 1; i++){
+          if( sqlite3Isdigit(z[i])==0 ){
+            if( z[i]==SQLITE_DIGIT_SEPARATOR ){ *tokenType = TK_QNUMBER; }
+            else{ break; }
+          }
+        }
       }
       if( (z[i]=='e' || z[i]=='E') &&
            ( sqlite3Isdigit(z[i+1]) 
             || ((z[i+1]=='+' || z[i+1]=='-') && sqlite3Isdigit(z[i+2]))
            )
       ){
-        i += 2;
-        while( sqlite3Isdigit(z[i]) ){ i++; }
-        *tokenType = TK_FLOAT;
+        if( *tokenType==TK_INTEGER ) *tokenType = TK_FLOAT;
+        for(i+=2; 1; i++){
+          if( sqlite3Isdigit(z[i])==0 ){
+            if( z[i]==SQLITE_DIGIT_SEPARATOR ){ *tokenType = TK_QNUMBER; }
+            else{ break; }
+          }
+        }
       }
 #endif
       while( IdChar(z[i]) ){
diff --git a/src/util.c b/src/util.c
index 207b901bad..24eff14e9f 100644
--- a/src/util.c
+++ b/src/util.c
@@ -311,6 +311,27 @@ void sqlite3DequoteExpr(Expr *p){
   sqlite3Dequote(p->u.zToken);
 }
 
+/*
+** Expression p is a QINTEGER or QFLOAT (quoted integer or float). Dequote
+** the value in p->u.zToken and set the type to INTEGER or FLOAT. "Quoted"
+** integers or floats are those that contain '_' characters that must
+** be removed before further processing.
+*/
+void sqlite3DequoteNumber(Expr *p){
+  if( p ){
+    const char *pIn = p->u.zToken;
+    char *pOut = p->u.zToken;
+    assert( p->op==TK_QNUMBER );
+    p->op = TK_INTEGER;
+    do {
+      if( *pIn!=SQLITE_DIGIT_SEPARATOR ){
+        *pOut++ = *pIn;
+        if( *pIn=='e' || *pIn=='E' || *pIn=='.' ) p->op = TK_FLOAT;
+      }
+    }while( *pIn++ );
+  }
+}
+
 /*
 ** If the input token p is quoted, try to adjust the token to remove
 ** the quotes.  This is not always possible:
diff --git a/test/literal.test b/test/literal.test
index 7bbb8f0f7a..8537ab5935 100644
--- a/test/literal.test
+++ b/test/literal.test
@@ -44,4 +44,7 @@ test_literal 1.12 '-0xFF'            text -0xFF
 test_literal 1.13 -'0xFF'            integer 0
 
 
+test_literal 2.1  1_000 integer 1000
+
+
 finish_test
diff --git a/test/speedtest1.c b/test/speedtest1.c
index 4f32580987..5709423818 100644
--- a/test/speedtest1.c
+++ b/test/speedtest1.c
@@ -2150,6 +2150,50 @@ void testset_debug1(void){
   }
 }
 
+/*
+** This testset focuses on the speed of parsing numeric literals (integers
+** and real numbers). This was added to test the impact of allowing "_"
+** characters to appear in numeric SQL literals to make them easier to read. 
+** For example, "SELECT 1_000_000;" instead of "SELECT 1000000;".
+*/
+void testset_parsenumber(void){
+  const char *zSql1 = "SELECT 1, 12, 123, 1234, 12345, 123456";
+  const char *zSql2 = "SELECT 8227256643844975616, 7932208612563860480, "
+                      "2010730661871032832, 9138463067404021760, "
+                      "2557616153664746496, 2557616153664746496";
+  const char *zSql3 = "SELECT 1.0, 1.2, 1.23, 123.4, 1.2345, 1.23456";
+  const char *zSql4 = "SELECT 8.227256643844975616, 7.932208612563860480, "
+                      "2.010730661871032832, 9.138463067404021760, "
+                      "2.557616153664746496, 2.557616153664746496";
+
+  const int NROW = 100*g.szTest;
+  int ii;
+
+  speedtest1_begin_test(100, "parsing small integers");
+  for(ii=0; ii<NROW; ii++){
+    sqlite3_exec(g.db, zSql1, 0, 0, 0);
+  }
+  speedtest1_end_test();
+
+  speedtest1_begin_test(110, "parsing large integers");
+  for(ii=0; ii<NROW; ii++){
+    sqlite3_exec(g.db, zSql2, 0, 0, 0);
+  }
+  speedtest1_end_test();
+
+  speedtest1_begin_test(200, "parsing small reals");
+  for(ii=0; ii<NROW; ii++){
+    sqlite3_exec(g.db, zSql3, 0, 0, 0);
+  }
+  speedtest1_end_test();
+
+  speedtest1_begin_test(210, "parsing large reals");
+  for(ii=0; ii<NROW; ii++){
+    sqlite3_exec(g.db, zSql4, 0, 0, 0);
+  }
+  speedtest1_end_test();
+}
+
 #ifdef __linux__
 #include <sys/types.h>
 #include <unistd.h>
@@ -2557,6 +2601,8 @@ int main(int argc, char **argv){
       testset_fp();
     }else if( strcmp(zThisTest,"trigger")==0 ){
       testset_trigger();
+    }else if( strcmp(zThisTest,"parsenumber")==0 ){
+      testset_parsenumber();
     }else if( strcmp(zThisTest,"rtree")==0 ){
 #ifdef SQLITE_ENABLE_RTREE
       testset_rtree(6, 147);
diff --git a/tool/speed-check.sh b/tool/speed-check.sh
index 4cc25794a2..5d425c3b37 100644
--- a/tool/speed-check.sh
+++ b/tool/speed-check.sh
@@ -161,6 +161,9 @@ while test "$1" != ""; do
     --fp)
         SPEEDTEST_OPTS="$SPEEDTEST_OPTS --testset fp"
         ;;
+    --parsenumber)
+        SPEEDTEST_OPTS="$SPEEDTEST_OPTS --testset parsenumber"
+        ;;
     --stmtscanstatus)
         SPEEDTEST_OPTS="$SPEEDTEST_OPTS --stmtscanstatus"
         ;;