diff --git a/manifest b/manifest
index 65c2202bec..0db5d0a578 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Take\scare\sthat\sthe\scode\sis\snot\sgenerated\sfor\sthe\ssame\sSelect\sobject\smore\nthan\sonce,\sas\stransformations\sthat\sapply\sduring\sthe\sfirst\spass\smight\ncause\sproblems\sfor\sthe\ssecond\spass.\ndbsqlfuzz\s836b625cd8a41809ef80fc7ebaa6554357bcb463.
-D 2021-05-26T18:46:51.922
+C Improvements\sto\sthe\sconstant-propagation\soptimization\sin\sorder\sto\sbetter\ndeal\swith\sunusual\saffinities.\s\sSee\n[forum:/forumpost/6a06202608|forum\spost\s6a06202608]\sfor\smore\sdetail.
+D 2021-05-26T23:10:19.141
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -544,7 +544,7 @@ F src/printf.c 78fabb49b9ac9a12dd1c89d744abdc9b67fd3205e62967e158f78b965a29ec4b
 F src/random.c 80f5d666f23feb3e6665a6ce04c7197212a88384
 F src/resolve.c 40e216d9a72e52841a9c8e0aec7d367bade8e2df17b804653b539b20c1ab5660
 F src/rowset.c ba9515a922af32abe1f7d39406b9d35730ed65efab9443dc5702693b60854c92
-F src/select.c 90e68ce9825dfcfed66c913c40dabf9d1c18232e6163ccf0eb83a062426b1aca
+F src/select.c f2d664297fccfe3eff7ac3b4e387ddb5cda1d53300f262d881869055b2299b85
 F src/shell.c.in 2a2b06d463933ee3a5bb0242d5d2200ca36769493fd6f4d939a0574113f3d6d8
 F src/sqlite.h.in 5c950066775ca9efdaa49077c05d38d0bef6418f3bd07d2dce0210f1d2f3c326
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
@@ -1765,6 +1765,7 @@ F test/whereI.test c4bb7e2ca56d49bd8ab5c7bd085b8b83e353922b46904d68aefb3c7468643
 F test/whereJ.test fc05e374cc9f2dc204148d6c06822c380ad388895fe97a6d335b94a26a08aecf
 F test/whereK.test 0270ab7f04ba5436fb9156d31d642a1c82727f4c4bfe5ba90d435c78cf44684a
 F test/whereL.test 50171e3ec00b4c8ad5ec773119a35d9e9642cec45154b44c366d628326479f4d
+F test/whereM.test 0dbc9998783458ddcf3cc078ca7c2951d8b2677d472ecf0028f449ed327c0250
 F test/wherefault.test 6cf2a9c5712952d463d3f45ebee7f6caf400984df51a195d884cfb7eb0e837a7
 F test/wherelfault.test 9012e4ef5259058b771606616bd007af5d154e64cc25fa9fd4170f6411db44e3
 F test/wherelimit.test afb46397c6d7e964e6e294ba3569864a0c570fe3807afc634236c2b752372f31
@@ -1916,7 +1917,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 3e2c36a8272ab3c1777638c0ed8222e7ff04657fe1c40f74a63b99a5a90258cc
-R b10ce1f99358565d3f53c557419950f3
+P f30fb19ff763a7cbe768ea49954704e14d6400f69bb4257c9c890e1564e14835 f17dec40a0ccc044bd32e035fc10797552329af242408a45f36125ed8d2ef088
+R f9b4579ee085374536d0f78bf690bce2
+T +closed f17dec40a0ccc044bd32e035fc10797552329af242408a45f36125ed8d2ef088
 U drh
-Z fbb7a8e7a5ceee7fc65ff6d53906cc32
+Z 8281f9c417505202be530b0457855632
diff --git a/manifest.uuid b/manifest.uuid
index 1962ec5c1f..706d1f3968 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-f30fb19ff763a7cbe768ea49954704e14d6400f69bb4257c9c890e1564e14835
\ No newline at end of file
+9be208a6d70582c6808abe6e016ab9cd8d10f0deefb8c7a8c0543372cca15b12
\ No newline at end of file
diff --git a/src/select.c b/src/select.c
index 5e2655c41f..d10518a39e 100644
--- a/src/select.c
+++ b/src/select.c
@@ -4417,6 +4417,7 @@ struct WhereConst {
   Parse *pParse;   /* Parsing context */
   int nConst;      /* Number for COLUMN=CONSTANT terms */
   int nChng;       /* Number of times a constant is propagated */
+  int bHasAffBlob; /* At least one column in apExpr[] as affinity BLOB */
   Expr **apExpr;   /* [i*2] is COLUMN and [i*2+1] is VALUE */
 };
 
@@ -4455,6 +4456,9 @@ static void constInsert(
       return;  /* Already present.  Return without doing anything. */
     }
   }
+  if( sqlite3ExprAffinity(pColumn)==SQLITE_AFF_BLOB ){
+    pConst->bHasAffBlob = 1;
+  }
 
   pConst->nConst++;
   pConst->apExpr = sqlite3DbReallocOrFree(pConst->pParse->db, pConst->apExpr,
@@ -4496,26 +4500,34 @@ static void findConstInWhere(WhereConst *pConst, Expr *pExpr){
 }
 
 /*
-** This is a Walker expression callback.  pExpr is a candidate expression
-** to be replaced by a value.  If pExpr is equivalent to one of the
-** columns named in pWalker->u.pConst, then overwrite it with its
-** corresponding value.
+** This is a helper function for Walker callback propagateConstantExprRewrite().
+**
+** Argument pExpr is a candidate expression to be replaced by a value. If 
+** pExpr is equivalent to one of the columns named in pWalker->u.pConst, 
+** then overwrite it with the corresponding value. Except, do not do so
+** if argument bIgnoreAffBlob is non-zero and the affinity of pExpr
+** is SQLITE_AFF_BLOB.
 */
-static int propagateConstantExprRewrite(Walker *pWalker, Expr *pExpr){
+static int propagateConstantExprRewriteOne(
+  WhereConst *pConst,
+  Expr *pExpr, 
+  int bIgnoreAffBlob
+){
   int i;
-  WhereConst *pConst;
   if( pExpr->op!=TK_COLUMN ) return WRC_Continue;
   if( ExprHasProperty(pExpr, EP_FixedCol|EP_FromJoin) ){
     testcase( ExprHasProperty(pExpr, EP_FixedCol) );
     testcase( ExprHasProperty(pExpr, EP_FromJoin) );
     return WRC_Continue;
   }
-  pConst = pWalker->u.pConst;
   for(i=0; i<pConst->nConst; i++){
     Expr *pColumn = pConst->apExpr[i*2];
     if( pColumn==pExpr ) continue;
     if( pColumn->iTable!=pExpr->iTable ) continue;
     if( pColumn->iColumn!=pExpr->iColumn ) continue;
+    if( bIgnoreAffBlob && sqlite3ExprAffinity(pColumn)==SQLITE_AFF_BLOB ){
+      break;
+    }
     /* A match is found.  Add the EP_FixedCol property */
     pConst->nChng++;
     ExprClearProperty(pExpr, EP_Leaf);
@@ -4527,6 +4539,41 @@ static int propagateConstantExprRewrite(Walker *pWalker, Expr *pExpr){
   return WRC_Prune;
 }
 
+/*
+** This is a Walker expression callback. pExpr is a node from the WHERE
+** clause of a SELECT statement. This function examines pExpr to see if
+** any substitutions based on the contents of pWalker->u.pConst should
+** be made to pExpr or its immediate children.
+**
+** A substitution is made if:
+**
+**   + pExpr is a column with an affinity other than BLOB that matches
+**     one of the columns in pWalker->u.pConst, or
+**
+**   + pExpr is a binary comparison operator (=, <=, >=, <, >) that
+**     uses an affinity other than TEXT and one of its immediate
+**     children is a column that matches one of the columns in 
+**     pWalker->u.pConst.
+*/
+static int propagateConstantExprRewrite(Walker *pWalker, Expr *pExpr){
+  WhereConst *pConst = pWalker->u.pConst;
+  assert( TK_GT==TK_EQ+1 );
+  assert( TK_LE==TK_EQ+2 );
+  assert( TK_LT==TK_EQ+3 );
+  assert( TK_GE==TK_EQ+4 );
+  if( pConst->bHasAffBlob ){
+    if( (pExpr->op>=TK_EQ && pExpr->op<=TK_GE)
+     || pExpr->op==TK_IS
+    ){
+      propagateConstantExprRewriteOne(pConst, pExpr->pLeft, 0);
+      if( sqlite3ExprAffinity(pExpr->pLeft)!=SQLITE_AFF_TEXT ){
+        propagateConstantExprRewriteOne(pConst, pExpr->pRight, 0);
+      }
+    }
+  }
+  return propagateConstantExprRewriteOne(pConst, pExpr, pConst->bHasAffBlob);
+}
+
 /*
 ** The WHERE-clause constant propagation optimization.
 **
@@ -4575,6 +4622,7 @@ static int propagateConstants(
     x.nConst = 0;
     x.nChng = 0;
     x.apExpr = 0;
+    x.bHasAffBlob = 0;
     findConstInWhere(&x, p->pWhere);
     if( x.nConst ){
       memset(&w, 0, sizeof(w));
diff --git a/test/whereM.test b/test/whereM.test
new file mode 100644
index 0000000000..83436893e8
--- /dev/null
+++ b/test/whereM.test
@@ -0,0 +1,112 @@
+# 2021 May 27
+#
+# 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.
+#
+#***********************************************************************
+# Tests focused on the "constant propagation" that occurs within the
+# WHERE clause of a SELECT statemente.
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+source $testdir/malloc_common.tcl
+set testprefix whereM
+
+
+do_execsql_test 1.0 {
+  CREATE TABLE t1(a, b INTEGER, c TEXT, d REAL, e BLOB);
+  INSERT INTO t1 VALUES(10.0, 10.0, 10.0, 10.0, 10.0);
+  SELECT * FROM t1;
+} {
+  10.0 10 10.0 10.0 10.0
+}
+
+do_execsql_test 1.1.1 {
+  SELECT a=10, a = '10.0', a LIKE '10.0' FROM t1;
+} {1 0 1}
+do_execsql_test 1.1.2 {
+  SELECT count(*) FROM t1 WHERE a=10 AND a = '10.0'
+} {0}
+do_execsql_test 1.1.3 {
+  SELECT count(*) FROM t1 WHERE a=10 AND a LIKE '10.0'
+} {1}
+do_execsql_test 1.1.4 {
+  SELECT count(*) FROM t1 WHERE a='10.0' AND a LIKE '10.0'
+} {0}
+
+do_execsql_test 1.2.1 {
+  SELECT b=10, b = '10.0', b LIKE '10.0', b LIKE '10' FROM t1;
+} {1 1 0 1}
+do_execsql_test 1.2.2 {
+  SELECT count(*) FROM t1 WHERE b=10 AND b = '10.0'
+} {1}
+do_execsql_test 1.2.3 {
+  SELECT count(*) FROM t1 WHERE b=10 AND b LIKE '10.0'
+} {0}
+do_execsql_test 1.2.4 {
+  SELECT count(*) FROM t1 WHERE b='10.0' AND b LIKE '10.0'
+} {0}
+do_execsql_test 1.2.3 {
+  SELECT count(*) FROM t1 WHERE b=10 AND b LIKE '10'
+} {1}
+do_execsql_test 1.2.4 {
+  SELECT count(*) FROM t1 WHERE b='10.0' AND b LIKE '10'
+} {1}
+
+do_execsql_test 1.3.1 {
+  SELECT c=10, c = 10.0, c = '10.0', c LIKE '10.0' FROM t1;
+} {0 1 1 1}
+do_execsql_test 1.3.2 {
+  SELECT count(*) FROM t1 WHERE c=10 AND c = '10.0'
+} {0}
+do_execsql_test 1.3.3 {
+  SELECT count(*) FROM t1 WHERE c=10 AND c LIKE '10.0'
+} {0}
+do_execsql_test 1.3.4 {
+  SELECT count(*) FROM t1 WHERE c='10.0' AND c LIKE '10.0'
+} {1}
+do_execsql_test 1.3.5 {
+  SELECT count(*) FROM t1 WHERE c=10.0 AND c = '10.0'
+} {1}
+do_execsql_test 1.3.6 {
+  SELECT count(*) FROM t1 WHERE c=10.0 AND c LIKE '10.0'
+} {1}
+
+do_execsql_test 1.4.1 {
+  SELECT d=10, d = 10.0, d = '10.0', d LIKE '10.0', d LIKE '10' FROM t1;
+} {1 1 1 1 0}
+do_execsql_test 1.4.2 {
+  SELECT count(*) FROM t1 WHERE d=10 AND d = '10.0'
+} {1}
+do_execsql_test 1.4.3 {
+  SELECT count(*) FROM t1 WHERE d=10 AND d LIKE '10.0'
+} {1}
+do_execsql_test 1.4.4 {
+  SELECT count(*) FROM t1 WHERE d='10.0' AND d LIKE '10.0'
+} {1}
+do_execsql_test 1.4.5 {
+  SELECT count(*) FROM t1 WHERE d='10' AND d LIKE '10.0'
+} {1}
+
+do_execsql_test 1.5.1 {
+  SELECT e=10, e = '10.0', e LIKE '10.0', e LIKE '10' FROM t1;
+} {1 0 1 0}
+do_execsql_test 1.5.2 {
+  SELECT count(*) FROM t1 WHERE e=10 AND e = '10.0'
+} {0}
+do_execsql_test 1.5.3 {
+  SELECT count(*) FROM t1 WHERE e=10 AND e LIKE '10.0'
+} {1}
+do_execsql_test 1.5.4 {
+  SELECT count(*) FROM t1 WHERE e='10.0' AND e LIKE '10.0'
+} {0}
+do_execsql_test 1.5.5 {
+  SELECT count(*) FROM t1 WHERE e=10.0 AND e LIKE '10.0'
+} {1}
+
+finish_test