Get Column Names

How can I get column names from a table in SQL Server?

You can obtain this information and much, much more by querying the Information Schema views.

This sample query:

SELECT *
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = N'Customers'

Can be made over all these DB objects:

• CHECK_CONSTRAINTS
• COLUMN_DOMAIN_USAGE
• COLUMN_PRIVILEGES
• COLUMNS
• CONSTRAINT_COLUMN_USAGE
• CONSTRAINT_TABLE_USAGE
• DOMAIN_CONSTRAINTS
• DOMAINS
• KEY_COLUMN_USAGE
• PARAMETERS
• REFERENTIAL_CONSTRAINTS
• ROUTINES
• ROUTINE_COLUMNS
• SCHEMATA
• TABLE_CONSTRAINTS
• TABLE_PRIVILEGES
• TABLES
• VIEW_COLUMN_USAGE
• VIEW_TABLE_USAGE
• VIEWS

How can I get column names from a table in Oracle?

You can query the USER_TAB_COLUMNS table for table column metadata.

SELECT table_name, column_name, data_type, data_length
FROM USER_TAB_COLUMNS
WHERE table_name = 'MYTABLE'

How can I get column names from a table in SQL?

MYSQL, MS SQL and Postgresql (thanks @christophe)

SELECT COLUMN_NAME 
FROM INFORMATION_SCHEMA.COLUMNS 
WHERE 
    TABLE_SCHEMA = 'database_name'
AND TABLE_NAME = 'table_name'

PIVOT the results if you need column names in one line

MySQL query to get column names?

The best way is to use the INFORMATION_SCHEMA metadata virtual database. Specifically the INFORMATION_SCHEMA.COLUMNS table...

SELECT `COLUMN_NAME` 
FROM `INFORMATION_SCHEMA`.`COLUMNS` 
WHERE `TABLE_SCHEMA`='yourdatabasename' 
    AND `TABLE_NAME`='yourtablename';

It's VERY powerful, and can give you TONS of information without need to parse text (Such as column type, whether the column is nullable, max column size, character set, etc)...

Oh, and it's standard SQL (Whereas SHOW ... is a MySQL specific extension)...

For more information about the difference between SHOW... and using the INFORMATION_SCHEMA tables, check out the MySQL Documentation on INFORMATION_SCHEMA in general...

Just get column names from hive table

If you simply want to see the column names this one line should provide it without changing any settings:

describe database.tablename;

However, if that doesn't work for your version of hive this code will provide it, but your default database will now be the database you are using:

use database;
describe tablename;

How to dynamically get column names from TypeORM?

As proposed in the issue on repository of that library (link) can be solved by using

connection.getMetadata("User").columns

Retrieve name of column from its Index in Pandas

I think you need index columns names by position (python counts from 0, so for fourth column need 3):

colname = df.columns[pos]

Sample:

df = pd.DataFrame({'A':[1,2,3],
                   'B':[4,5,6],
                   'C':[7,8,9],
                   'D':[1,3,5],
                   'E':[5,3,6],
                   'F':[7,4,3]})

print (df)
   A  B  C  D  E  F
0  1  4  7  1  5  7
1  2  5  8  3  3  4
2  3  6  9  5  6  3

pos = 3
colname = df.columns[pos]
print (colname)
D

---

pos = [3,5]
colname = df.columns[pos]
print (colname)
Index(['D', 'F'], dtype='object')

Get column names AND types using star macro in dbt

You can view the source for dbt_utils.star here

Under the hood, it uses dbt_utils.get_filtered_columns_in_relation. That macro also just returns column names. However! that macro uses the built-in adapter.get_columns_in_relation, which returns a list of Column objects, which have a data_type property.

So your code becomes:

{% set all_columns = adapter.get_columns_in_relation(
    ref("my_table")
) %}
{% set except_col_names=["a", "b", "c"] %}

select 
    date_trunc('week', day) as week,
    name,

    {%- for col in all_columns if col.name not in except_col_names %}  
    {% if col.data_type == 'BOOLEAN' %}  
    max({{ col.name|lower }}) as {{ col.name|lower }}{%- if not loop.last %},{{ '\n  ' }}{% endif %}
    {% endif %}
    {%- endfor %}

from {{ ref('my_table_name') }}    
group by 1, 2

How to get column names from a query?

You can try this on a tJavaRow, following your DBInput component :

for (java.lang.reflect.Field field: row1.getClass().getDeclaredFields()) {
context.columnName = field.getName();
      System.out.println("Field name is " + context.columnName );      
           }

Spotted on talend help center here : https://community.talend.com/t5/Design-and-Development/resolved-how-to-get-the-column-names-in-a-data-flow/td-p/99172

You can extend this, and put the column list on your outputflow :

//add this inside the loop, and 'columnNames' as an output row in tJavaRow schema

             output_row.columnNames+=context.columnName+";";

With a tNormalize after tJavaRow, you shoud get the expected result.

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