'using an alias column in the where clause in PostgreSQL' - using an alias column in the where clause in PostgreSQL

problem ：

"

I have a query like this:<\/i> I have a query like this ：<\/b><\/p>

SELECT    jobs.*,     (        CASE            WHEN lead_informations.state IS NOT NULL THEN lead_informations.state            ELSE 'NEW'        END    ) AS lead_stateFROM    jobs    LEFT JOIN lead_informations ON        lead_informations.job_id = jobs.id        AND        lead_informations.mechanic_id = 3WHERE    lead_state = 'NEW'

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Solution ：

Reference resources ： https://stackoom.com/en/question/DbDs