mysql - SQL returning null results when queried -



mysql - SQL returning null results when queried -

i'm doing bring together statement 2 database tables. here's code , output:

code select recurrentemergencies.day, emergencies.systems, emergencies.descriptions, emergencies.breakers emergencies right bring together recurrentemergencies on recurrentemergencies.systems = emergencies.systems order emergencies.descriptions; output day systems descriptions breakers 1 null null null 1 null null null 0 null null null 0 null null null 1 null null null 1 null null null 1 null null null 0 null null null

doing left bring together partially right, returns correctly, duplicates each row in the emergencies table.

day systems descriptions breakers 1 avionics ads 2 fail avionics[2] 1 avionics ads 2 fail avionics[2] 1 avionics ads 2 fail avionics[2] 1 avionics ads 2 fail avionics[2] 1 avionics ads 2 fail avionics[2] 1 avionics ads 2 fail avionics[2] 1 apu apu high oil temperature apu [4] 1 apu apu high oil temperature apu [4] 1 apu apu high oil temperature apu [4] 1 apu apu high oil temperature apu [4]

the 2 tables similar, differences day column , number of rows in each table. so, since i'm comparing 2 similar columns in 2 tables, why getting null values?

mysql sql

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