Examples of org.apache.tajo.algebra.NamedExpr

org.apache.tajo.algebra.NamedExpr
NamedExpr is an expression which can be aliased in a target list.
```
 SELECT col1 + col2 as a, sum(col2) as b, col3 as c, col4, ... FROM ... ^^^^^^^^^^^^^^^^  ^^^^^^^^^^^^^^  ^^^^^^^^^  ^^^^ expr1             expr2        expr3    expr4 
```
We define each expression in expr1 - expr4 as a named expression. In database community, each of them is called target or an expression in a select list, Each expression can be explicitly aliased as an given name.

    return idToExprBiMap.get(nameToIdMap.get(name));
  }


  public NamedExpr getNamedExpr(String name) {
    String normalized = name;
    return new NamedExpr(getExpr(name), normalized);
  }

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  }


  public Collection<NamedExpr> getAllNamedExprs() {
    List<NamedExpr> namedExprList = Lists.newArrayList();
    for (Map.Entry<Integer, Expr> entry: idToExprBiMap.entrySet()) {
      namedExprList.add(new NamedExpr(entry.getValue(), idToNamesMap.get(entry.getKey()).get(0)));
    }
    return namedExprList;
  }

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      List<NamedExpr> unEvaluatedList = TUtil.newList();
      for (Integer refId: idToNamesMap.keySet()) {
        String name = idToNamesMap.get(refId).get(0);
        if (!isEvaluated(name)) {
          Expr expr = idToExprBiMap.get(refId);
          unEvaluatedList.add(new NamedExpr(expr, name));
        }
      }
      if (unEvaluatedList.size() == 0) {
        iterator = null;
      } else {

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Related Classes of org.apache.tajo.algebra.NamedExpr

org.apache.tajo.engine.planner.NamedExprsManager

org.apache.tajo.engine.planner.NamedExprsManager$UnevaluatedIterator

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