几个left join连接起来表示什么意思?
首先看一段代码：
select sar.markerallel1 || sar.markerallel2 as markeralleleselements, sg.auditor, si.*, sar.*, ci.* from sample_info si left join sample_audit_result sar on si.sample_id = sar.sample_id left join case_info ci on ci.case_id = si.case_id left join sample_gene sg on si.sample_id = sg.sample_id where si.IS_DELETED <> 1 and si.ACCEPT_STATUS = 1 and sg.audit_status = '1' and si.case_id in (select case_id from case_info where case_base_info_id in (select case_base_info_id from case_info where case_id = '04dd3a01-e6a3-4489-a694-f8daf3e36cc8')) and sg.id in (select sample_gene_id from sample_audit_result sar) and si.barcode in (select sample_barcode from sample_audit_result sar) order by length(si.barcode), si.bar
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几个left join 连一块，读起来比较费劲，不知从何下手?
