Aliases 即 AS 存在兼容性问题：不支持单双引号；无法与 count 函数共同使用

[ipaddicting]

Bug Description
Aliases 即 AS 存在兼容性问题：

首先，AS 不支持单双引号，即 " 和 '

taos> SELECT TIMETRUNCATE(ts, 1d, 0) AS ts, max(engine_load) AS "max(engine_load)" FROM abacus.log_combikat GR
OUP BY TIMETRUNCATE(ts, 1d, 0) ORDER BY engine_load DESC;
DB error: syntax error near ""max(engine_load)" from abacus.log_combikat group by timetruncate(ts, 1d, 0) order by engine_load desc;" (0.000060s)

去除 ' 或 " 后仅支持简单字符，但存在歧义：

taos> SELECT TIMETRUNCATE(ts, 1d, 0) AS ts, max(engine_load) AS engine_load FROM abacus.log_combikat GROUP BY
TIMETRUNCATE(ts, 1d, 0) ORDER BY engine_load DESC;
           ts            |     engine_load      |
=================================================
 2016-02-08 00:00:00.000 |          -24.3999996 |
 2016-02-04 00:00:00.000 |          -24.3999996 |
 2016-02-17 00:00:00.000 |          -24.3999996 |
 2016-02-18 00:00:00.000 |          -24.3999996 |
 2016-02-13 00:00:00.000 |          -24.3999996 |
 2016-02-02 00:00:00.000 |          -24.3999996 |
 2016-02-07 00:00:00.000 |          -24.3999996 |
 2016-02-14 00:00:00.000 |          -24.3999996 |
 2016-02-19 00:00:00.000 |          -24.3999996 |
 2016-02-06 00:00:00.000 |          -24.3999996 |
 2016-02-12 00:00:00.000 |          -24.3999996 |
 2016-02-03 00:00:00.000 |          -24.3999996 |
 2016-02-15 00:00:00.000 |          -24.3999996 |
 2016-02-16 00:00:00.000 |          -24.3999996 |
 2016-02-29 00:00:00.000 |          -24.5000000 |
 2016-02-01 00:00:00.000 |          -24.5000000 |
 2016-02-24 00:00:00.000 |          -24.5000000 |
 2016-02-27 00:00:00.000 |          -24.5000000 |
 2016-02-22 00:00:00.000 |          -24.5000000 |
 2016-02-11 00:00:00.000 |          -24.5000000 |
 2016-02-10 00:00:00.000 |          -24.5000000 |
 2016-02-21 00:00:00.000 |          -24.5000000 |
 2016-02-20 00:00:00.000 |          -24.5000000 |
 2016-02-28 00:00:00.000 |          -24.5000000 |
 2016-02-25 00:00:00.000 |          -24.5000000 |
 2016-02-09 00:00:00.000 |          -24.5000000 |
 2016-02-05 00:00:00.000 |          -24.5000000 |
 2016-02-26 00:00:00.000 |          -24.5000000 |
 2016-02-23 00:00:00.000 |          -24.5000000 |
Query OK, 29 row(s) in set (0.011580s)

不支持单双引号导致与其他软件如 Superset 存在兼容问题：

Error: [0x2600]: syntax error near ""MAX(engine_load)" 
from abacus.log_combikat group by timetruncate(ts, 1d, 0) order by "MAX(engine_load)" desc
 limit 10000"

其次，COUNT 函数无法使用 AS，报错如下：

taos> SELECT TIMETRUNCATE(ts, 1d, 0) AS ts, count(*) AS count FROM abacus.log_combikat GROUP BY TIMETRUNCATE(t
s, 1d, 0);
DB error: syntax error near "count from abacus.log_combikat group by timetruncate(ts, 1d, 0);" (0.000144s)

移除 AS 可正常查询：

taos> SELECT TIMETRUNCATE(ts, 1d, 0) AS ts, count(*) FROM abacus.log_combikat GROUP BY TIMETRUNCATE(ts, 1d, 0)
           ts            |       count(*)        |
==================================================
 2016-02-05 00:00:00.000 |                   286 |
 2016-02-11 00:00:00.000 |                   282 |
 2016-02-16 00:00:00.000 |                   286 |
 2016-02-06 00:00:00.000 |                   286 |
 2016-02-15 00:00:00.000 |                   286 |
 2016-02-10 00:00:00.000 |                   284 |
 2016-02-21 00:00:00.000 |                   288 |
 2016-02-20 00:00:00.000 |                   288 |
 2016-02-28 00:00:00.000 |                   288 |
 2016-02-14 00:00:00.000 |                   286 |
 2016-02-25 00:00:00.000 |                   288 |
 2016-02-17 00:00:00.000 |                   286 |
 2016-02-18 00:00:00.000 |                   286 |
 2016-02-09 00:00:00.000 |                   286 |
 2016-02-23 00:00:00.000 |                   287 |
 2016-02-02 00:00:00.000 |                   286 |
 2016-02-26 00:00:00.000 |                   288 |
 2016-02-22 00:00:00.000 |                   287 |
 2016-02-27 00:00:00.000 |                   287 |
 2016-02-07 00:00:00.000 |                   286 |
 2016-02-29 00:00:00.000 |                   288 |
 2016-02-13 00:00:00.000 |                   286 |
 2016-02-04 00:00:00.000 |                   286 |
 2016-02-19 00:00:00.000 |                   288 |
 2016-02-01 00:00:00.000 |                   286 |
 2016-02-24 00:00:00.000 |                   288 |
 2016-02-03 00:00:00.000 |                   286 |
 2016-02-12 00:00:00.000 |                   285 |
 2016-02-08 00:00:00.000 |                   286 |
Query OK, 29 row(s) in set (0.009566s)

To Reproduce
参考以上 SQL 语句。

Expected Behavior

1. AS 需支持单双引号；
2. AS 可以与 COUNT 函数共同使用。

Environment (please complete the following information):

• OS: 官方镜像
• TDengine Version 3.3.0.0

Additional Context
目前我正在尝试将 taospy 集成进 Superset 的过程中，相关代码会在集成验证完成后提交 taospy 以及 Superset 合并，谢谢。