Ensure that the expression of a virtual column really is an expression and

not just a reference to another column, as a real expression is necessary for
the indexed expression coverage optimization to work properly.
[forum:/forumpost/07b36e3899a9ae21|Forum thread 07b36e3899a9ae21].

FossilOrigin-Name: 40549bacb3923e439627b0103bedd7da30258b69a46960040f7176e060f51f2f

1 files changed, 7 insertions, 0 deletions

diff --git a/src/build.c b/src/build.c
index 29a798e6c..415eeae70 100644
--- a/src/build.c
+++ b/src/build.c
@@ -2004,6 +2004,13 @@ void sqlite3AddGenerated(Parse *pParse, Expr *pExpr, Token *pType){
   if( pCol->colFlags & COLFLAG_PRIMKEY ){
     makeColumnPartOfPrimaryKey(pParse, pCol); /* For the error message */
   }
+  if( ALWAYS(pExpr) && pExpr->op==TK_ID ){
+    /* The value of a generated column needs to be a real expression, not
+    ** just a reference to another column, in order for covering index
+    ** optimizations to work correctly.  So if the value is not an expression,
+    ** turn it into one by adding a unary "+" operator. */
+    pExpr = sqlite3PExpr(pParse, TK_UPLUS, pExpr, 0);
+  }
   sqlite3ColumnSetExpr(pParse, pTab, pCol, pExpr);
   pExpr = 0;
   goto generated_done;