postgresql join query

Question

I have two tables T1 and T2

T1
-id
-columnA
-columnB
-columnC

T2
-id
-columnX
-columnY
-columnZ

I have a query like

Select t1.* t2.columnZ 
from T1 t1 
  left join on T2 t2 on t1.id = t2.id 
where t2.columnZ = 'test'

I want result like if "where t2.columnZ = 'test'" does not return any row then it should return value of columnZ as null value

can you explain what the output you required ?

Shubham Batra
– Shubham Batra

2015-12-22 11:13:58 +00:00
Commented Dec 22, 2015 at 11:13 — Shubham Batra
– Shubham Batra, Commented Dec 22, 2015 at 11:13

HoneyBadger · Accepted Answer · 2015-12-22 11:57:39Z

3

Try:

SELECT    t1.*
,         t2.columnZ
FROM      T1 t1
LEFT JOIN T2 t2 
       ON t1.id = t2.id
      AND t2.columnZ = 'test'

You also missed a comma, and you had a misplaced on.

edited Dec 22, 2015 at 11:57

answered Dec 22, 2015 at 10:27

HoneyBadger

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1 Comment

HoneyBadger Over a year ago

@wingedpanther, I replaced the original where with and, with where selects only those that have 'test'. The question, as I understood it, is to get a complete set, some may have 'test' others not. I also don't get your edit, what was the point?

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