feature: Added support for simple CAST

[mlilius]

This will not handle all versions of CAST but will handle a simple case like CAST(pct*100 AS int)

The query mentioned in #9 was used as the test.

select
    concat(dsw_cluster_name,',',logic_pod_name) as event_obj,
    concat(dsw_cluster_name,',',logic_pod_name, ' PFC STORM. 详情: ',
    '流量突跃 ',
    cast(FLOW_RX_BPS_RATE100 as int),
    '%(RX)',
    '; ',
    cast(FLOW_TX_BPS_RATE100 as int),
    '%(TX)',
    '; PFC 突增 ',
    cast(PFC_RX_PPS_RATE*100 as int),
    '%(RECV)') as brief
from SOURCE_BASIC_EVENT_POD_FLOW_AND_PFC_TREND
where win_end >= '2020-05-19 21:14:12'
    and win_end < '2020-05-20 21:14:12'
    and PFC_RX_PPS_RATE >= 100
    and (FLOW_RX_BPS_RATE <= -0.2 and FLOW_TX_BPS_RATE <= -0.2)

[albin3]

hello @mlilius , CHARACTER SET grammar should be supported in this feature follows https://dev.mysql.com/doc/refman/5.7/en/cast-functions.html . see examples : "SELECT CAST('test' AS CHAR CHARACTER SET utf8 COLLATE utf8_bin);"