如何获取特定行的列值的计数？

Question

I have a table below.

how to get the count of the column value whose value is 'M' in a particular row?

ex: If i give the condition, where shape_name='Rectangle' it will return the count of the column whose value is = 'M'. Result: count is 2

If True L-Left=> Result: count is 4 How to get the answer.? plz help me to fix it.

Answer 1

A solution with CASE WHEN is like this:

SELECT shape_name,
      CASE WHEN a = 'm' THEN 1 ELSE 0 END +
      CASE WHEN b = 'm' THEN 1 ELSE 0 END +
      CASE WHEN c = 'm' THEN 1 ELSE 0 END as mcount
  FROM t1

SQLFiddle

Just adjust the SQL to your table structure - you will need to find more CASE WHEN statements for each column

Answer 2

非常古老的解决方案 - 获取所有列，遍历所有列，并计算M出现次数。

Answer 3

  select SHAPE_NAME ,
            DECODE(COLUMN_NAME1,'M',1,0)+
            DECODE(COLUMN_NAME2,'M',1,0)+
            DECODE(COLUMN_NAME3,'M',1,0)+
            DECODE(COLUMN_NAME4,'M',1,0) your_count
 from  YOUR_TABLE where shape_name='Rectangle' ;