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Yes this do solve my problem. But shouldn't coalesce produce an empty array when there is no data in books?

PaxPrz
– PaxPrz

2021-01-14 04:11:25 +00:00
Commented Jan 14, 2021 at 4:11
4

@Pax: COALESCE can only step in when there is a row to begin with.

Erwin Brandstetter
– Erwin Brandstetter

2021-01-14 04:58:00 +00:00
Commented Jan 14, 2021 at 4:58

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