使用LambdaWrapper实现去重查询方式
<div id="navCategory"><h5 class="catalogue">目录</h5><ul class="first_class_ul"><li><a href="#_label0">用LambdaWrapper去实现去重查询</a></li><ul class="second_class_ul"><li><a href="#_lab2_0_0">我们知道</a></li><li><a href="#_lab2_0_1">QueryWrapper转换成LambdaWrapper</a></li></ul><li><a href="#_label1">总结</a></li><ul class="second_class_ul"></ul></ul></div><p class="maodian"><a name="_label0"></a></p><h2>用LambdaWrapper去实现去重查询</h2><p class="maodian"><a name="_lab2_0_0"></a></p><h3>我们知道</h3>
<p>LambdaWrapper比较好用，但是LambdaWrapper却不能实现<code>select(String s)</code></p>
<p>那只需要进行QueryWrapper与LambdaQueryWrapper的混合使用就可以了，所以巧妙转换很重要</p>
<div class="jb51code"><pre class="brush:sql;">@Override
public Integer getCountAbPressure(String customerId, LocalDateTime firstDay, LocalDateTime lastDay, List<String> list, Integer type) {
QueryWrapper<CustomerBodyMetricsEntity> wrapper = new QueryWrapper<>();
wrapper.select("DISTINCT version")
.lambda()
.eq(CustomerBodyMetricsEntity::getCustomerId, customerId)
.ge(CustomerBodyMetricsEntity::getVersion, DateTimeUtil.dateTimeToTimestamp(firstDay))
.le(CustomerBodyMetricsEntity::getVersion, DateTimeUtil.dateTimeToTimestamp(lastDay))
.in(CustomerBodyMetricsEntity::getMetric, list)
.ne(CustomerBodyMetricsEntity::getLabel, 20);
return this.count(wrapper);
}
</pre></div>
<p class="maodian"><a name="_lab2_0_1"></a></p><h3>QueryWrapper转换成LambdaWrapper</h3>
<p>只需要<code>lambda()</code>方法即可</p>
<p class="maodian"><a name="_label1"></a></p><h2>总结</h2>
<p>以上为个人经验，希望能给大家一个参考，也希望大家多多支持琼殿技术社区。</p>
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