函数运算符
https://blog.csdn.net/lihaiyong92/article/details/72900848
字符串函数
https://blog.csdn.net/du1055669885/article/details/83787508
https://www.yiibai.com/html/postgresql/2013/080893.html?1375917742
时间/日期函数使用
https://blog.csdn.net/qq_36011279/article/details/82622159
数字函数
https://www.yiibai.com/html/postgresql/2013/080892.html?1375917723
聚合函数
https://yq.aliyun.com/articles/144
扩展
coalesce ():返回参数列表中,第一个非空值。
extract:从日期或者时间数值里面抽取子域 引用:https://blog.csdn.net/nextaction/article/details/76473613
ANY : 传入多个条件拼接的数据
String obj = '001,002,003'
a = ANY (string_to_array(obj ,','))
行号:ROW_NUMBER() OVER( [ PRITITION BY col1] ORDER BY col2[ DESC ] )
获取某月的天数
EXTRACT( DAY FROM date_trunc('DAY',TO_DATE(TO_CHAR(date,'yyyy/MM'),'yyyy/MM')) + INTERVAL '1 MONTH' - INTERVAL '1 DAY') AS max_day
完善中。。。