Fix EXPLAIN QUERY PLAN output for indexed-expressions. Fix another

obscure fault in the WHERE term scanner.

FossilOrigin-Name: 73d361ce9e4d72c943def8b0b3caa227f9199aed

2 files changed, 14 insertions, 7 deletions

diff --git a/src/where.c b/src/where.c
index c78563f1c..8d26cd4b4 100644
--- a/src/where.c
+++ b/src/where.c
@@ -191,10 +191,9 @@ static WhereTerm *whereScanNext(WhereScan *pScan){
         ){
           if( (pTerm->eOperator & WO_EQUIV)!=0
            && pScan->nEquiv<ArraySize(pScan->aiCur)
+           && (pX = sqlite3ExprSkipCollate(pTerm->pExpr->pRight))->op==TK_COLUMN
           ){
             int j;
-            pX = sqlite3ExprSkipCollate(pTerm->pExpr->pRight);
-            assert( pX->op==TK_COLUMN );
             for(j=0; j<pScan->nEquiv; j++){
               if( pScan->aiCur[j]==pX->iTable
                && pScan->aiColumn[j]==pX->iColumn ){
diff --git a/src/wherecode.c b/src/wherecode.c
index e5c0b40b1..0a9d7b35b 100644
--- a/src/wherecode.c
+++ b/src/wherecode.c
@@ -42,6 +42,16 @@ static void explainAppendTerm(
 }
 
 /*
+** Return the name of the i-th column of the pIdx index.
+*/
+static const char *explainIndexColumnName(Index *pIdx, int i){
+  i = pIdx->aiColumn[i];
+  if( i==(-2) ) return "<expr>";
+  if( i==(-1) ) return "rowid";
+  return pIdx->pTable->aCol[i].zName;
+}
+
+/*
 ** Argument pLevel describes a strategy for scanning table pTab. This 
 ** function appends text to pStr that describes the subset of table
 ** rows scanned by the strategy in the form of an SQL expression.
@@ -60,13 +70,11 @@ static void explainIndexRange(StrAccum *pStr, WhereLoop *pLoop, Table *pTab){
   u16 nEq = pLoop->u.btree.nEq;
   u16 nSkip = pLoop->nSkip;
   int i, j;
-  Column *aCol = pTab->aCol;
-  i16 *aiColumn = pIndex->aiColumn;
 
   if( nEq==0 && (pLoop->wsFlags&(WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))==0 ) return;
   sqlite3StrAccumAppend(pStr, " (", 2);
   for(i=0; i<nEq; i++){
-    char *z = aiColumn[i] < 0 ? "rowid" : aCol[aiColumn[i]].zName;
+    const char *z = explainIndexColumnName(pIndex, i);
     if( i>=nSkip ){
       explainAppendTerm(pStr, i, z, "=");
     }else{
@@ -77,11 +85,11 @@ static void explainIndexRange(StrAccum *pStr, WhereLoop *pLoop, Table *pTab){
 
   j = i;
   if( pLoop->wsFlags&WHERE_BTM_LIMIT ){
-    char *z = aiColumn[j] < 0 ? "rowid" : aCol[aiColumn[j]].zName;
+    const char *z = explainIndexColumnName(pIndex, i);
     explainAppendTerm(pStr, i++, z, ">");
   }
   if( pLoop->wsFlags&WHERE_TOP_LIMIT ){
-    char *z = aiColumn[j] < 0 ? "rowid" : aCol[aiColumn[j]].zName;
+    const char *z = explainIndexColumnName(pIndex, j);
     explainAppendTerm(pStr, i, z, "<");
   }
   sqlite3StrAccumAppend(pStr, ")", 1);