Merge conflicts.

1 files changed, 27 insertions, 0 deletions

diff --git a/lib/libsqlite3/src/parse.y b/lib/libsqlite3/src/parse.y
index ad9bedf0b47..dbc129ce638 100644
--- a/lib/libsqlite3/src/parse.y
+++ b/lib/libsqlite3/src/parse.y
@@ -1020,6 +1020,33 @@ expr(A) ::= expr(W) between_op(N) expr(X) AND expr(Y). [BETWEEN] {
       */
       A.pExpr = sqlite3PExpr(pParse, TK_INTEGER, 0, 0, &sqlite3IntTokens[N]);
       sqlite3ExprDelete(pParse->db, X.pExpr);
+    }else if( Y->nExpr==1 ){
+      /* Expressions of the form:
+      **
+      **      expr1 IN (?1)
+      **      expr1 NOT IN (?2)
+      **
+      ** with exactly one value on the RHS can be simplified to something
+      ** like this:
+      **
+      **      expr1 == ?1
+      **      expr1 <> ?2
+      **
+      ** But, the RHS of the == or <> is marked with the EP_Generic flag
+      ** so that it may not contribute to the computation of comparison
+      ** affinity or the collating sequence to use for comparison.  Otherwise,
+      ** the semantics would be subtly different from IN or NOT IN.
+      */
+      Expr *pRHS = Y->a[0].pExpr;
+      Y->a[0].pExpr = 0;
+      sqlite3ExprListDelete(pParse->db, Y);
+      /* pRHS cannot be NULL because a malloc error would have been detected
+      ** before now and control would have never reached this point */
+      if( ALWAYS(pRHS) ){
+        pRHS->flags &= ~EP_Collate;
+        pRHS->flags |= EP_Generic;
+      }
+      A.pExpr = sqlite3PExpr(pParse, N ? TK_NE : TK_EQ, X.pExpr, pRHS, 0);
     }else{
       A.pExpr = sqlite3PExpr(pParse, TK_IN, X.pExpr, 0, 0);
       if( A.pExpr ){