我当前正在尝试计算其中包含不同值的列。
我感兴趣的列是 routes ，但是我遇到的问题是该列的数据类型是VARCHAR。
我想知道是否有一种方法可以计算此列中出现的不同事件。
+---------+-------------------------+-----------------------------+-----------------------------------------------+-----------+------------+-----------------+----------+-----------------------------+
| stop_id | on_street | cross_street | routes | boardings | alightings | month_beginning | day_type | location |
+---------+-------------------------+-----------------------------+-----------------------------------------------+-----------+------------+-----------------+----------+-----------------------------+
| 1 | JACKSON | AUSTIN | 126 | 183 | 150 | 2012-10-01 | Weekday | (41.87632184, -87.77410482) |
| 48 | HARRISON | WOOD | 126 | 1 | 2 | 2012-10-01 | Weekday | (41.87405900, -87.67133400) |
| 50 | ASHLAND | CONGRESS | 9,126 | 15 | 27 | 2012-10-01 | Weekday | (41.87508698, -87.66643194) |
| 52 | JACKSON | 1900 W.(MALCOLM X COLL.) | 126 | 83 | 229 | 2012-10-01 | Weekday | (41.87743988, -87.67402389) |
| 69 | JACKSON | FINANCIAL PLACE | 1,7,X28,126,129,130,132,151 | 118 | 185 | 2012-10-01 | Weekday | (41.87808100, -87.63286800) |
| 71 | JACKSON | STATE | 1,7,X28,126,129,130 | 201 | 750 | 2012-10-01 | Weekday | (41.87814100, -87.62789900) |
| 73 | MICHIGAN | betw. VAN BUREN & CONGRES | 1,3,4,7,J14,26,X28,126,129,132,143,147,148 | 966 | 922 | 2012-10-01 | Weekday | (41.87627100, -87.62439600) |
| 75 | MICHIGAN | VAN BUREN | 1,7,X28,126,129 | 290 | 91 | 2012-10-01 | Weekday | (41.87669000, -87.62416000) |