# TSDIFF
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Returns NULL if any of the arguments is null.

 Otherwise returns the difference between the two timestamps in milliseconds.

## Syntax
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```
TSDIFF(startTime, endTime)
```

## Parameters
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*startTime*

A Unix timestamp in the format milliseconds since '1970-01-01 00:00:00' UTC, expressed as a BIGINT.

*endTime*

A Unix timestamp in the format milliseconds since '1970-01-01 00:00:00' UTC, expressed as a BIGINT.