-- Table info
SELECT s.TABLE_SCHEMA || '.' || s.SYSTEM_TABLE_NAME, s.TABLE_TYPE, s.TABLE_SCHEMA || '.' || s.TABLE_NAME, s.TABLE_TEXT FROM QSYS2.SYSTABLES s 
where s.TABLE_SCHEMA = 'MYSCHEMA' -- OR: CURRENT_SCHEMA
ORDER BY s.TABLE_NAME 


-- Table + Column info
SELECT  sc.TABLE_SCHEMA || '.' || sc.TABLE_NAME, s.TABLE_TEXT, sc.SYSTEM_COLUMN_NAME, sc.COLUMN_NAME, sc.COLUMN_TEXT, sc.DATA_TYPE, sc.LENGTH, sc.IS_NULLABLE
from QSYS2.SYSCOLUMNS sc
JOIN QSYS2.SYSTABLES s ON s.TABLE_NAME = sc.TABLE_NAME AND s.TABLE_SCHEMA = sc.TABLE_SCHEMA 
where sc.TABLE_SCHEMA = 'MYSCHEMA' -- OR: CURRENT_SCHEMA
AND s.TABLE_NAME = 'MY_TABLE' OR s.SYSTEM_TABLE_NAME = 'MY_TABLE'
ORDER BY sc.ORDINAL_POSITION