FIND_IN_SET mysql的最终结果是逻辑判断，还有注意字段是否有大小写
m: FIND_IN_SET(b.my_building_project_id in a.my_building_project_phase_id)
g: position(UPPER(b.my_building_project_id) in UPPER(a.my_building_project_phase_id))>0
行列转换
string_agg(t2,',') tt1
SELECT t1,string_agg(t2,',') tt1 from test.test1 GROUP BY t1
a b,c
b a,g
regexp_split_to_table(t3.tt1,',')
SELECT t3.t1,regexp_split_to_table(t3.tt1,',') from
(
SELECT t1,string_agg(t2,',') tt1 from test.test1 GROUP BY t1 )t3 GROUP BY t3.t1,t3.tt1
b a
b g
a b
a c
SELECT regexp_split_to_table(t3.tt1,',') from
(
SELECT string_agg(t2,',') tt1 from test.test1 GROUP BY t1 )t3
比较字段有大小写
UPPER(a.my_building_project_id)=UPPER(b.building_father_id)
数值类型的判断
m:a.order_status !=-1
g: a.order_status <>-1
时间比较
m:TIMESTAMPDIFF(DAY,date(max(a.create_time)),ifnull(b.sign_time,now())) days_diff
m:TIMESTAMPDIFF(HOUR,a.create_time,b.create_time)<=168
注意顺序
g: date_part('epoch', b.create_time::TIMESTAMP-a.create_time::TIMESTAMP)>=604800
求出秒
SELECT date_part('epoch', '2019-05-06 12:00:00'::TIMESTAMP -'2019-05-03 11:30:01'::TIMESTAMP)::NUMERIC;
分组计算
SELECT t1,t2,t3,rank() over(PARTITION BY t1 ORDER BY t3) as t4 from test.test1
b g 3 1
b a 7 2
a b 8 1
a c 9 2
时间2
-- DATE(enter_time) =DATE_ADD(CURRENT_DATE,INTERVAL -1 day)
gp select date(CURRENT_DATE+interval '-1 day');
m SELECT DATE_ADD(CURRENT_DATE,INTERVAL -1 day)
group_concat
gp：string_agg(字段,'分隔符')
多字段合并
GP:concat_ws('分隔符'，字段，字段)
空值设置为0
g SELECT COALESCE(null,0)
m SELECT ifnull(null,0)
除法
m：SUM(a.stop_seconds)/36000 默认是带小数
g：SUM(a.stop_seconds)/36000 默认是取整数
decode(string text, format text) bytea 把用string表示的文本里面的二进制数据解码。 format选项和encode相同。 decode('MTIzAAE=', 'base64') \x3132330001
g：SUM(a.stop_seconds)/36000::numeric
二进制转换
m:SELECT from_base64('6IyD5q2j5YW0')
g:SELECT convert_from(decode('6IyD5q2j5YW0', 'base64'),'utf8')
convert_from(string bytea, src_encoding name) text 把原来编码为src_encoding的字符串转换为数据库编码格式。 这种编码格式中，string必须是有效的。 convert_from('text_in_utf8', 'UTF8') text_in_utf8 用当前数据库编码表示
decode(string text, format text) bytea 把用string表示的文本里面的二进制数据解码。 format选项和encode相同。 decode('MTIzAAE=', 'base64') \x3132330001
http://postgres.cn/docs/9.4/functions-string.html
SUBSTRING_INDEX(from_id,'@',-1)
CREATE OR REPLACE FUNCTION substring_index(varchar, varchar, integer)
RETURNS varchar AS $$
DECLARE
tokens varchar[];
length integer ;
indexnum integer;
BEGIN
tokens := pg_catalog.string_to_array($1, $2);
length := pg_catalog.array_upper(tokens, 1);
indexnum := length - ($3 * -1) + 1;
IF $3 >= 0 THEN
RETURN pg_catalog.array_to_string(tokens[1:$3], $2);
ELSE
RETURN pg_catalog.array_to_string(tokens[indexnum:length], $2);
END IF;
END;
$$ IMMUTABLE STRICT LANGUAGE PLPGSQL;
FILTER的使用
gp:
SELECT c.openid,
MIN(createtime) FILTER (where c.wxconfigid='xxxxx') as n
from wxmgr_user c
group by c.openid
mysql
SELECT c.openid,
MIN(case when c.wxconfigid='xxxxx' then c.createtime else '2099-01-01 00:00:00' end) as n
from wxmgr_user c
group by c.openid
时间段
mysql：上周从周一开始
(a.create_time >= concat(ADDDATE(DATE_SUB(CURDATE(),INTERVAL WEEKDAY(CURDATE()) + 1 DAY),-6),' ','00:00:00') AND
a.create_time < concat(DATE_SUB(CURDATE(),INTERVAL WEEKDAY(CURDATE()) DAY),' ','00:00:00'))
gp:
(a.create_time >= CURRENT_DATE - (extract(DOW from CURRENT_DATE)+6 || ' day')::interval AND
a.create_time < CURRENT_DATE - (extract(DOW from CURRENT_DATE)-1 || ' day')::interval)
昨天
mysql：ADDDATE(CURRENT_DATE,INTERVAL -1 DAY)
gp：CURRENT_DATE-integer '1'
显示年月
mysql：DATE_FORMAT(a.day,'%Y-%m')
gp: to_char(a.day,'YYYY-MM')
SELECT to_char(now(),'YYYY-MM-DD HH24:MI:SS') now;