我有两个像这样的表:
表gene_names:
+------------------+------------------+
| gene_alias | gene_name |
+------------------+------------------+
| AC148152.3_FG007 | AC148152.3_FG007 |
| AC149829.2_FG002 | AC149829.2_FG002 |
| AC149829.2_FG004 | AC149829.2_FG004 |
| AC155352.2_FG009 | AC155352.2_FG009 |
| AC155352.2_FG012 | AC155352.2_FG012 |
+------------------+------------------+
另一个名为gene_transcripts的表:
+-------------------+------------------+
| transcript_alias | gene_alias |
+-------------------+------------------+
| AC148152.3_FGT007 | AC148152.3_FG007 |
| AC149829.2_FGT002 | AC149829.2_FG002 |
| AC149829.2_FGT004 | AC149829.2_FG004 |
| AC155352.2_FGT009 | AC155352.2_FG009 |
| AC155352.2_FGT012 | AC155352.2_FG012 |
+-------------------+------------------+
我想要的是从 gene_transcripts 获取 gene_alias 并从 gene_names 获取 gene_name。为此，我这样做(示例):
SELECT gene_transcripts.gene_alias,
gene_names.gene_name
FROM gene_transcripts,
gene_names
WHERE gene_transcripts.gene_alias="AT4G38300_oG.1"
AND gene_transcripts.gene_alias=gene_names.gene_alias;
它没有给出任何结果，因为gene_alias“AT4G38300_oG.1”在表gene_names中没有条目。到目前为止，看起来非常合乎逻辑、合理。
我想要得到的是(我不知道如何实现这一点，因此我在这里问这个问题)，是如何获得以下输出:
+-------------------+------------------+
| transcript_alias | gene_alias |
+-------------------+------------------+
| AT4G38300_oG.1 | NULL |
+-------------------+------------------+
这可能吗？
最佳答案
只需使用左连接
select
gt.gene_alias as transcript_alias,
gn.gene_name as gene_alias
from gene_transcripts gt
left join gene_names gn on gt.gene_alias=gn.gene_alias
where gt.gene_alias="AT4G38300_oG.1"
关于mysql - 在 MySQL 查询中获取 NULL 值，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/24573178/