how to select column names in sql code example

Example 1: get table columns from sql

SELECT *
FROM INFORMATION_SCHEMA.COLUMNS 
WHERE TABLE_NAME = N'Customers' 
-- INFORMATION_SCHEMA is an ANSI-standard (American National Standard Institute) set of read-only views which provide information about all of the tables, views, columns, and procedures in a database
-- "N" defines the subsequent string (the string after the N) as being in unicode

Example 2: sql server list of columns in a table

SELECT 
    c.name 'Column Name',
    t.Name 'Data type',
    c.max_length 'Max Length',
    c.precision ,
    c.scale ,
    c.is_nullable,
    ISNULL(i.is_primary_key, 0) 'Primary Key'
FROM    
    sys.columns c
INNER JOIN 
    sys.types t ON c.user_type_id = t.user_type_id
LEFT OUTER JOIN 
    sys.index_columns ic ON ic.object_id = c.object_id AND ic.column_id = c.column_id
LEFT OUTER JOIN 
    sys.indexes i ON ic.object_id = i.object_id AND ic.index_id = i.index_id
WHERE
    c.object_id = OBJECT_ID('YourTableName')