Esta es mi última consulta (pivotizada):
SELECT c.COLUMN_NAME,
--c.COLUMN_KEY,
IF(EXISTS(select *
FROM information_schema.KEY_COLUMN_USAGE k
JOIN information_schema.TABLE_CONSTRAINTS tc
ON (k.TABLE_SCHEMA=tc.TABLE_SCHEMA
AND k.TABLE_NAME=tc.TABLE_NAME
AND k.CONSTRAINT_NAME=tc.CONSTRAINT_NAME)
WHERE k.TABLE_SCHEMA=c.TABLE_SCHEMA
AND k.TABLE_NAME=c.TABLE_NAME
AND tc.CONSTRAINT_TYPE='PRIMARY KEY'
AND c.COLUMN_NAME=k.COLUMN_NAME),'PK',null) AS PK,
IF(EXISTS(select *
FROM information_schema.KEY_COLUMN_USAGE k
JOIN information_schema.TABLE_CONSTRAINTS tc
ON (k.TABLE_SCHEMA=tc.TABLE_SCHEMA
AND k.TABLE_NAME=tc.TABLE_NAME
AND k.CONSTRAINT_NAME=tc.CONSTRAINT_NAME)
WHERE k.TABLE_SCHEMA=c.TABLE_SCHEMA
AND k.TABLE_NAME=c.TABLE_NAME
AND tc.CONSTRAINT_TYPE='UNIQUE'
AND c.COLUMN_NAME=k.COLUMN_NAME),'UQ',null) AS UQ,
IF(EXISTS(select *
FROM information_schema.KEY_COLUMN_USAGE k
JOIN information_schema.TABLE_CONSTRAINTS tc
ON (k.TABLE_SCHEMA=tc.TABLE_SCHEMA
AND k.TABLE_NAME=tc.TABLE_NAME
AND k.CONSTRAINT_NAME=tc.CONSTRAINT_NAME)
WHERE k.TABLE_SCHEMA=c.TABLE_SCHEMA
AND k.TABLE_NAME=c.TABLE_NAME
AND tc.CONSTRAINT_TYPE='FOREIGN KEY'
AND c.COLUMN_NAME=k.COLUMN_NAME),'FK',null) AS FK,
c.EXTRA,
c.IS_NULLABLE,
c.DATA_TYPE,
c.COLUMN_TYPE,
c.CHARACTER_MAXIMUM_LENGTH,
c.COLUMN_COMMENT,
k.REFERENCED_TABLE_SCHEMA,
k.REFERENCED_TABLE_NAME,
k.REFERENCED_COLUMN_NAME
FROM information_schema.COLUMNS c
LEFT JOIN information_schema.KEY_COLUMN_USAGE k
ON (k.TABLE_SCHEMA=c.TABLE_SCHEMA
AND k.TABLE_NAME=c.TABLE_NAME
AND k.COLUMN_NAME=c.COLUMN_NAME
AND k.POSITION_IN_UNIQUE_CONSTRAINT IS NOT NULL)
WHERE c.TABLE_SCHEMA='PHPDAO'
AND c.TABLE_NAME='employees';
Pero creo que tiene que haber una solución más sencilla.
