Primary Key Column Check | Dataford Interview Questions

Write SQL queries to check if the row is a primary column.

Use the supplied metadata tables to determine whether each registered column belongs to a primary key constraint. Include columns without matching constraints and distinguish primary key constraints from other constraint types.

Output

One row per registered column.
Columns: table_schema, table_name, column_name, and is_primary_key.
Sort by schema, table name, and column ID.

Schema

catalog_columns

Column	Type	Description
column_idPK	INT	Unique metadata identifier for a column
table_id	INT	Identifier of the table containing the column
table_schema	VARCHAR(63)	Database schema name
table_name	VARCHAR(63)	Table name
column_name	VARCHAR(63)	Column name

table_constraints

Column	Type	Description
constraint_idPK	INT	Unique constraint identifier
table_id	INT	Identifier of the constrained table
constraint_name	VARCHAR(100)	Constraint name
is_primary_key	BOOLEAN	Whether the constraint is a primary key

constraint_columns

Column	Type	Description
constraint_idPK	INT	Referenced constraint identifier
column_idPK	INT	Referenced column identifier
ordinal_position	INT	Column position within the constraint

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Problem