Oracle: Usage

Талбаруудын өгөгдлийн төрлийг харах.
Select the column datatype using case when, concat function.

SELECT column_name,
CASE
WHEN data_type = 'DATE' then data_type
WHEN data_type = 'NUMBER' then concat( concat( concat( data_type, '(' ), concat( data_precision, case when data_scale > 0 then concat( ',', data_scale) end ) ), ')' )
WHEN data_type = 'NVARCHAR2' then concat( concat( concat( data_type, '(' ), char_length), ')' )
WHEN data_type = 'VARCHAR2' then concat( concat( concat( data_type, '(' ), concat( char_length, case char_used when 'B' then ' BYTE' end ) ), ')' )
END data_type
FROM user_tab_columns
WHERE table_name='table_name' AND (
column_name = 'columnname1' OR
column_name = 'columnname2' OR
column_name = 'columnname3'
) order by column_name;

Output:
COLUMN_NAME DATA_TYPE
columnname1 NUMBER(4)
columnname2 VARCHAR2(15 BYTE)
columnname3 DATE