zeros - ClickHouse Documentation

zeros(N) – Returns a table with the single ‘zero’ column (UInt8) that contains the integer 0 N times
zeros_mt(N) – The same as zeros, but uses multiple threads.

This function is used for test purposes as the fastest method to generate many rows. Similar to the system.zeros and system.zeros_mt system tables. The following queries are equivalent:

SELECT * FROM zeros(10);
SELECT * FROM system.zeros LIMIT 10;
SELECT * FROM zeros_mt(10);
SELECT * FROM system.zeros_mt LIMIT 10;

┌─zero─┐
│    0 │
│    0 │
│    0 │
│    0 │
│    0 │
│    0 │
│    0 │
│    0 │
│    0 │
│    0 │
└──────┘

Last modified on June 6, 2026

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