Postgres Aliasing

Question

我正在使用PostgreSQL和Pentaho数据集成。我正在执行查询：

  SELECT
  t.VAL_1 as Contract,
  t.VAL_2 as Calender,
  t.VAL_3 as MSPProvider,
  t.VAL_4 as MSPCustomer,
  t.VAL_5 as Severity,
  t.VAL_6 as Relation,
  t.VAL_7 as Target,
  t.VAL_8 as TargetUnit,
  t.VAL_9 as TargetPeriod,
  t.VAL_10 as CalculationType,
  t.VAL_11 as working_days,
  t.VAL_12 as time_of_day
FROM t_slalom_outputs t 
WHERE t.is_active = 1 and t.table_name = 'contract_target_mapping';

错误说：

ERROR:  column t.val_1 does not exist

LINE 1: select t.VAL_1 as Contract,
               ^
********** Error **********

ERROR: column t.val_1 does not exist
SQL state: 42703
Character: 8

如果我使用带引号的逗号来编写查询，即

 SELECT
 't.VAL_1' as Contract,
  't.VAL_2' as Calender,
  't.VAL_3' as MSPProvider,
  't.VAL_4' as MSPCustomer,
  't.VAL_5' as Severity,
  't.VAL_6' as Relation,
  't.VAL_7' as Target,
  't.VAL_8' as TargetUnit,
  't.VAL_9' as TargetPeriod,
  't.VAL_10' as CalculationType,
  't.VAL_11' as working_days,
  't.VAL_12' as time_of_day
 FROM t_slalom_outputs t 

列名(t.val_1,t.val_2.....t.val_12)将填充在列值中，列名称为别名（合同，日历.......时间）。我想执行第一个查询，但无法摆脱错误。我是PostgreSQL的noobie。我认为语法有些错误。任何帮助将不胜感激。