Get Data from Table with Column as Rows in MYSQL - mysql

Question

Can any one help me with a query that converts column into rows and then find data accordingly.
The question is below. I have tried a query that gets the column names into rows but i was unable to get values or had any idea to figure it out for column3 and column 4. I am a new bibe in SQL. Can anyone help me out here. I heard from a friend suggesting pivot and when i browse i found PIVOT is not supported in MYSQL
Input Table:
E1 E2 E3 E4 E5 E6
Null 1234 234 12 A B
123 Null Null Null 12 B
Null Null Null Null Null Null
123 2 1 A 1 2
Output Table:
C1 C2 Count TotalC percent
E1 123 2 2 1
E2 1234 1 2 0.5
E2 2 1 2 0.5
E3 234 1 2 0.5
E3 1 1 2 0.5
E4 12 1 2 0.5
E4 A 1 2 0.5
E5 A 1 3 0.3
E5 12 1 3 0.3
E5 1 1 3 0.3
E6 B 2 3 0.6
E6 2 1 3 0.3
Explanation of the Question:
C1 is the Column names of input table.
C2 is the data in those columns.
Count is the number of similar items and singles in each columns.
TotalC is the number of total not null values.
percent is the count/totalc.
Query i worked : SELECT (COLUMN_NAME)AS Column1 FROM INFORMATION_SCHEMA.COLUMNS WHERE table_name = 'inputtable';
Note: query in MYSQL.

Answer 1

As mentioned in my comment above, you should probably handle this problem differently. See What is the XY problem?
However, if you must, you can solve this problem using UNION:
SELECT *, Count/TotalC AS percent
FROM (
SELECT 'E1' AS C1, E1 AS C2, COUNT(*) AS Count
FROM Input
WHERE E1 IS NOT NULL
GROUP BY C2
UNION ALL
SELECT 'E2' AS C1, E2 AS C2, COUNT(*) AS Count
FROM Input
WHERE E2 IS NOT NULL
GROUP BY C2
UNION ALL
SELECT 'E3' AS C1, E3 AS C2, COUNT(*) AS Count
FROM Input
WHERE E3 IS NOT NULL
GROUP BY C2
UNION ALL
SELECT 'E4' AS C1, E4 AS C2, COUNT(*) AS Count
FROM Input
WHERE E4 IS NOT NULL
GROUP BY C2
UNION ALL
SELECT 'E5' AS C1, E5 AS C2, COUNT(*) AS Count
FROM Input
WHERE E5 IS NOT NULL
GROUP BY C2
UNION ALL
SELECT 'E6' AS C1, E6 AS C2, COUNT(*) AS Count
FROM Input
WHERE E6 IS NOT NULL
GROUP BY C2
) t1 NATURAL JOIN (
SELECT 'E1' AS C1, COUNT(E1) AS TotalC FROM Input
UNION ALL
SELECT 'E2' AS C1, COUNT(E2) AS TotalC FROM Input
UNION ALL
SELECT 'E3' AS C1, COUNT(E3) AS TotalC FROM Input
UNION ALL
SELECT 'E4' AS C1, COUNT(E4) AS TotalC FROM Input
UNION ALL
SELECT 'E5' AS C1, COUNT(E5) AS TotalC FROM Input
UNION ALL
SELECT 'E6' AS C1, COUNT(E6) AS TotalC FROM Input
) t2
See it on sqlfiddle.