Sql Server: Find out default value of a column with a query

Diving deeper into default value retrieval

While the quick answer provides the straight-to-the-point solution, there are also deeper considerations and more complex scenarios you might face when working with default values.

Schema specific extraction

For SQL environments with multiple schemas, adjust your query to specify TABLE_SCHEMA, ensuring accuracy:

SELECT COLUMN_DEFAULT
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_SCHEMA = 'YourSchemaName' AND TABLE_NAME = 'YourTableName' AND COLUMN_NAME = 'YourColumnName';
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Deployment of object_definition

The object_definition() function offers a more detailed glimpse into the contextual fabric of default constraints, including any mathematical gymnastics or shapeshifting functions within:

SELECT object_definition(default_object_id) as DefaultValueContext
FROM sys.columns
WHERE name = 'YourColumnName' AND object_id = object_id('YourSchemaName.YourTableName');
/* Oh blame Merlin's beard! It talks! */


Dynamic default value detective work

For those moments when you long to dynamically unearth default values across your database, the trusty sys tables provide a portkey to your destination:

SELECT 
    col.name as ColumnName,  
    object_definition(def.default_object_id) as DefaultValue
FROM 
    sys.columns col
    LEFT JOIN sys.default_constraints def ON col.default_object_id = def.object_id
WHERE 
    col.object_id = object_id('YourSchemaName.YourTableName');
/* Congratulations! You've been promoted to a SQL Sherlock! */


Harnessing this method, you can reveal the default values for all columns in a specified table with pleasing precision.

The impact and importance of default values

Grasping the significance and role of default values hones your SQL toolkit and upgrades your database management craft.

The guardian grails of default values

Acting as silent guardians, default values ensure no data column is left bare during insert operations, thus preserving a consistently dressed state within your database.

Dissecting data quality

By judiciously employing default values, you bolster data quality, warding off the creeping spectres of null-related errors, and securing a predictable behaviour for your database operations.