Skip to content
Coordinator DB
View as Markdown
View as Markdown

system.tables ​

Lists tables and views across registered databases and the observing connection's temporary namespace. Use database and schema_name to distinguish objects with the same name.

Columns ​

Name Meaning
database Managed database containing the object.
schema_name Namespace such as main or temp.
table_name Object name.
table_type Object classification, such as BASE TABLE or VIEW.
definition SQL definition text.
name Object-name field for compatible metadata queries.
create_table_query Creation SQL.
is_temporary Whether it is a temporary object.
total_rows Available row estimate, or NULL.
total_bytes Available byte estimate, or NULL.

The estimates are not a guarantee of an exact count. Use a concrete query when an exact result is required.

Example ​

sql
CREATE TABLE documented_table(id UInt32);
CREATE VIEW documented_view AS SELECT id FROM documented_table;
sql
SELECT table_name, table_type
FROM system.tables
WHERE table_name IN ('documented_table', 'documented_view')
  AND schema_name = 'main'
ORDER BY table_name
FORMAT csv;
text
"documented_table","BASE TABLE"
"documented_view","VIEW"

Management ​

Validated persistent catalog writes are supported for management. CREATE, ALTER and DROP are the normal object interface; the relation's observational fields are not arbitrary writable table data.

Use the system qualifier through a server interface. See system.columns for fields and SQL statements for object operations.