# if evaluation in precondition tag

**URL:** <https://forum.liquibase.org/t/if-evaluation-in-precondition-tag/3954>\
**Category:** Liquibase Development\
**Created:** [October 6, 2017, 7:06pm UTC](https://forum.liquibase.org/t/if-evaluation-in-precondition-tag/3954 "2017-10-06T19:06:00Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![AlessioFrabotta](https://avatars.discourse-cdn.com/v4/letter/a/8c91f0/32.png) [@AlessioFrabotta](https://forum.liquibase.org/u/AlessioFrabotta)\
**Post date:** [October 6, 2017, 7:06pm UTC](https://forum.liquibase.org/t/if-evaluation-in-precondition-tag/3954/1 "2017-10-06T19:06:00Z")

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I have a changeSet as follows:

  

The table “table\_pippo” on the db is not guaranteed.&nbsp; I get an error because all conditions in precondition are executed, but&nbsp;I was expecting that the precondition would return false without evaluating the second condition to the failure of the first condition.

  

Can anyone explain this behavior?

  

Thanks in advance

  

Alessio