Index: ext/expert/expert1.test
==================================================================
--- ext/expert/expert1.test
+++ ext/expert/expert1.test
@@ -461,7 +461,24 @@
   t1 t1_idx_000123a7 {100 50 17}
   t2 t2_idx_00000063 {100 20} 
   t2 t2_idx_00000064 {100 5} 
   t2 t2_idx_0001295b {100 20 5}
 }
+
+do_test expert1-6.0 {
+  catchcmd :memory: {
+.expert
+select base64('');
+.expert
+select name from pragma_collation_list order by name collate uint;
+}
+} {0 {(no new indexes)
+
+SCAN CONSTANT ROW
+
+(no new indexes)
+
+SCAN pragma_collation_list VIRTUAL TABLE INDEX 0:
+USE TEMP B-TREE FOR ORDER BY
+}}
 
 finish_test

Index: ext/expert/sqlite3expert.c
==================================================================
--- ext/expert/sqlite3expert.c
+++ ext/expert/sqlite3expert.c
@@ -30,11 +30,11 @@
 # define NEVER(X)       (X)
 #endif
 #endif /* !defined(SQLITE_AMALGAMATION) */
 
 
-#ifndef SQLITE_OMIT_VIRTUALTABLE 
+#ifndef SQLITE_OMIT_VIRTUALTABLE
 
 typedef sqlite3_int64 i64;
 typedef sqlite3_uint64 u64;
 
 typedef struct IdxColumn IdxColumn;
@@ -1817,10 +1817,91 @@
 
   sqlite3_exec(p->db, "DROP TABLE IF EXISTS temp."UNIQUE_TABLE_NAME,0,0,0);
   return rc;
 }
 
+/*
+** Define and possibly pretend to use a useless collation sequence.
+** This pretense allows expert to accept SQL using custom collations.
+*/
+int dummyCompare(void *up1, int up2, const void *up3, int up4, const void *up5){
+  (void)up1;
+  (void)up2;
+  (void)up3;
+  (void)up4;
+  (void)up5;
+  assert(0); /* VDBE should never be run. */
+  return 0;
+}
+/* And a callback to register above upon actual need */
+void useDummyCS(void *up1, sqlite3 *db, int etr, const char *zName){
+  (void)up1;
+  sqlite3_create_collation_v2(db, zName, etr, 0, dummyCompare, 0);
+}
+
+#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS) \
+  && !defined(SQLITE_OMIT_INTROSPECTION_PRAGMAS)
+/*
+** dummy functions for no-op implementation of UDFs during expert's work
+*/
+void dummyUDF(sqlite3_context *up1, int up2, sqlite3_value **up3){
+  (void)up1;
+  (void)up2;
+  (void)up3;
+  assert(0); /* VDBE should never be run. */
+}
+void dummyUDFvalue(sqlite3_context *up1){
+  (void)up1;
+  assert(0); /* VDBE should never be run. */
+}
+
+/*
+** Register UDFs from user database with another.
+*/
+int registerUDFs(sqlite3 *dbSrc, sqlite3 *dbDst){
+  sqlite3_stmt *pStmt;
+  int rc = sqlite3_prepare_v2(dbSrc,
+            "SELECT name,type,enc,narg,flags "
+            "FROM pragma_function_list() "
+            "WHERE builtin==0", -1, &pStmt, 0);
+  if( rc==SQLITE_OK ){
+    while( SQLITE_ROW==(rc = sqlite3_step(pStmt)) ){
+      int nargs = sqlite3_column_int(pStmt,3);
+      int flags = sqlite3_column_int(pStmt,4);
+      const char *name = (char*)sqlite3_column_text(pStmt,0);
+      const char *type = (char*)sqlite3_column_text(pStmt,1);
+      const char *enc = (char*)sqlite3_column_text(pStmt,2);
+      if( name==0 || type==0 || enc==0 ) rc = SQLITE_NOMEM;
+      else{
+        int ienc = SQLITE_UTF8;
+        if( strcmp(enc,"utf16le")==0 ) ienc = SQLITE_UTF16LE;
+        else if( strcmp(enc,"utf16be")==0 ) ienc = SQLITE_UTF16BE;
+        int rcf = SQLITE_ERROR;
+        ienc |= (flags & (SQLITE_DETERMINISTIC|SQLITE_DIRECTONLY));
+        if( strcmp(type,"w")==0 ){
+          rcf = sqlite3_create_window_function(dbDst,name,nargs,ienc,0,
+                                               dummyUDF,dummyUDFvalue,0,0,0);
+        }else if( strcmp(type,"a")==0 ){
+          rcf = sqlite3_create_function(dbDst,name,nargs,ienc,0,
+                                        0,dummyUDF,dummyUDFvalue);
+        }else if( strcmp(type,"s")==0 ){
+          rcf = sqlite3_create_function(dbDst,name,nargs,ienc,0,
+                                        dummyUDF,0,0);
+        }
+        if( rcf!=SQLITE_OK ){
+          rc = rcf;
+          break;
+        }
+      }
+    }
+    sqlite3_finalize(pStmt);
+    if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+  }
+  return rc;
+}
+#endif
+
 /*
 ** Allocate a new sqlite3expert object.
 */
 sqlite3expert *sqlite3_expert_new(sqlite3 *db, char **pzErrmsg){
   int rc = SQLITE_OK;
@@ -1843,11 +1924,25 @@
     rc = sqlite3_open(":memory:", &pNew->dbm);
     if( rc==SQLITE_OK ){
       sqlite3_db_config(pNew->dbm, SQLITE_DBCONFIG_TRIGGER_EQP, 1, (int*)0);
     }
   }
-  
+
+  /* Allow custom collations to be dealt with through prepare. */
+  if( rc==SQLITE_OK ) rc = sqlite3_collation_needed(pNew->dbm,0,useDummyCS);
+  if( rc==SQLITE_OK ) rc = sqlite3_collation_needed(pNew->dbv,0,useDummyCS);
+
+#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS) \
+  && !defined(SQLITE_OMIT_INTROSPECTION_PRAGMAS)
+  /* Register UDFs from database [db] with [dbm] and [dbv]. */
+  if( rc==SQLITE_OK ){
+    rc = registerUDFs(pNew->db, pNew->dbm);
+  }
+  if( rc==SQLITE_OK ){
+    rc = registerUDFs(pNew->db, pNew->dbv);
+  }
+#endif
 
   /* Copy the entire schema of database [db] into [dbm]. */
   if( rc==SQLITE_OK ){
     sqlite3_stmt *pSql = 0;
     rc = idxPrintfPrepareStmt(pNew->db, &pSql, pzErrmsg, 
@@ -1919,10 +2014,14 @@
 
   if( p->bRun ) return SQLITE_MISUSE;
 
   while( rc==SQLITE_OK && zStmt && zStmt[0] ){
     sqlite3_stmt *pStmt = 0;
+    /* Ensure that the provided statement compiles against user's DB. */
+    rc = idxPrepareStmt(p->db, &pStmt, pzErr, zStmt);
+    if( rc!=SQLITE_OK ) break;
+    sqlite3_finalize(pStmt);
     rc = sqlite3_prepare_v2(p->dbv, zStmt, -1, &pStmt, &zStmt);
     if( rc==SQLITE_OK ){
       if( pStmt ){
         IdxStatement *pNew;
         const char *z = sqlite3_sql(pStmt);