revert pr 587 failed to parse WHERE / GROUP BY clauses in a SELECT st…

…atement without a FROM table (#597)
pingcap · Oct 31, 2019 · bfb0c3a · bfb0c3a
1 parent 8839bb5
commit bfb0c3a
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Showing 4 changed files with 3,346 additions and 3,303 deletions.
diff --git a/ast/dml.go b/ast/dml.go
@@ -864,6 +864,9 @@ func (n *SelectStmt) Restore(ctx *RestoreCtx) error {
 		}
 	}
 
+	if n.From == nil && n.Where != nil {
+		ctx.WriteKeyWord(" FROM DUAL")
+	}
 	if n.Where != nil {
 		ctx.WriteKeyWord(" WHERE ")
 		if err := n.Where.Restore(ctx); err != nil {