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2021年03月
1.如果某些join的关联key相同,需按顺序放在一起,提高效率 2. 分析join是否有倾斜,有的话考虑切分热点数据,最后进行union all合并 3. 还可以看看时间是否可切分,不做全表关联,增量关联近xx天数据,补历史数据的情况下,每次运行只刷新近xx天数据
你好,你可以通过TRANS_ARRAY列转行函数,将一行数据转化为多行,将关联的key打开后再进行关联,使用如下,谢谢
+----------+----------+------------+
| login_id | login_ip | login_time |
+----------+----------+------------+
| wangwangA | 192.168.0.1,192.168.0.2 | 20120101010000,20120102010000 |
| wangwangB | 192.168.45.10,192.168.67.22,192,168.6.3 | 20120111010000,20120112010000,20120223080000 |
执行sql:
select trans_array(1, ",", login_id, login_ip, login_time) as (login_id,login_ip,login_time) from t_table;
产生的数据是
+----------+----------+------------+
| login_id | login_ip | login_time |
+----------+----------+------------+
| wangwangB | 192.168.45.10 | 20120111010000 |
| wangwangB | 192.168.67.22 | 20120112010000 |
| wangwangB | 192.168.6.3 | 20120223080000 |
| wangwangA | 192.168.0.1 | 20120101010000 |
| wangwangA | 192.168.0.2 | 20120102010000 |
1.max聚合函数,需把select中其他不聚合的字段,放到group by里 2. datediff的字段,需转换为datetime类型
应该是当时排队的作业太多,资源一直处于等待状态,杀掉任务,等资源不紧张后重试
建立日历表,以日历表为主表left outer join您的订单事实表,key为日期,通过coalesce(counts,0)将未关联出的订单则置为0,谢谢
你好,可以检查一下两边变量配置的计算逻辑是否相同,谢谢
你好,物理执行计划生成失败,原因是全表所有分区扫描,数据量太大,请指定具体分区
你好,框架都还适用,平台功能、函数大部分都适用,原理没有大改,可以买来入门学习
median函数目前限制在一个组内不超过100万行数据
你好,根据您字段类型不同而不同,以下参考:
类型 是否新类型 常量定义 描述
TINYINT 是 1Y,-127Y 8 位有符号整形,范围 -128 到 127
SMALLINT 是 32767S, -100S 16 位有符号整形, 范围 -32768 到 32767
INT 是 1000,-15645787(注释1) 32位有符号整形,范围-231到231 -1
BIGINT 否 100000000000L, -1L 64位有符号整形, 范围-263 + 1到263 - 1
FLOAT 是 无 32位二进制浮点型
DOUBLE 否 3.1415926 1E+7 8字节双精度浮点数,64位二进制浮点型
DECIMAL 否 3.5BD, 99999999999.9999999BD(注释4) 10 进制精确数字类型,整形部分范围-1036+1到1036-1, 小数部分精确到 10-18 。
VARCHAR(n) 是 无 ( 注释2 ) 变长字符类型,n为长度,取值范围 1 到 65535
STRING 否 “abc”,’bcd’,”alibaba” ‘inc’ ( 注释3 ) 字符串类型,目前长度限制为 8M
BINARY 是 无 二进制数据类型,目前长度限制为 8M
DATETIME 否 DATETIME ‘2017-11-11 00:00:00’ 日期时间类型,使用东八区时间作为系统标准时间。范围从0000年1月1日到9999年12月31日,精确到毫秒 。(注释5)
TIMESTAMP 是 TIMESTAMP ‘2017-11-11 00:00:00.123456789’ 范围从0000年1月1日到9999年12月31日 23.59:59.999999999, 精确到纳秒。注意:timestamp类型本身与时区无关,在任何时区,timestamp类型存储的都是从epoch(UTC 1970-01-01 00:00:00)开始的一个偏移量。您可以通过一些内置函数对timestamp类型数据进行与时区相关的计算,如cast(< a timestamp > as string)将timestamp类型数据按照当前时区值转换成string类型。
BOOLEAN 否 TRUE,FALSE boolean 类型, 取值 TRUE 或 FALSE
你好,wm_concat()可以支持分组排序后合并,具体使用方式:
string wm_concat(string separator, string str)
用途:用指定的spearator做分隔符,链接str中的值。
参数说明:
separator:String类型常量,分隔符。其他类型或非常量将引发异常。
str:String类型,若输入为bigint,double或者datetime类型会隐式转换为string后参与运算,其它类型报异常。
返回值:String类型。
备注:
对语句”select wm_concat(‘,’,name) from test_src;”,若test_src为空集合,这MaxCompute SQL条语句返回NULL值。
调大资源和并发
输入、输出表是必须需要指定的。如果读全表可不指定分区
select * from table where ds >= to_char(dateadd(to_date('${bizdate}', 'yyyymmdd'), -7, 'dd'),'yyyymmdd')
可以用round函数四舍五入计算到任意小数点后的位置
将A系统和B系统的表都抽入到MaxCompute里面的,如果是需要A系统和B系统的表关联加工来更新C表的话,可以通过数据开发,编写SQL脚本,一次性insert overwriteC表,进行更新。
如果insert overwrite分别更新的话,那么只保留最后一次更新的数据,前一次的就被覆盖掉了。
你好,由于ODPS的所有数据都被存放在表中,因此ODPS MapReduce的输入、输出只能是表,不允许用户自定义输出格式,不提供类似文件系统的接口,谢谢
你好,odpscmd中有一个conf文件,里面有一个odps_config.ini,在里面设置endpoint即可,谢谢。
把不等值放在关联之后的where中过滤,把b、c表中的过滤条件提到子查询中提前过滤数据量,减少join的数据量,望采纳,谢谢!
select a.*
from
(select * from tmp_t_mz_ry_jhdj)a
left join
(select * from t_jztp_gx_sum where gxxl like '1104%' and zgxr is null)b
on ((a.zgxr = b.zgxr and a.cgxr = b.cgxr) or
(a.zgxr = b.cgxr and a.cgxr = b.zgxr))
left join
(select * from tmp_t_mz_ry_lhdj where zgxr is null)c
on a.zgxr = c.zgxr
and a.cgxr = c.cgxr
where a.gxfssj < c.gxfssj;
A
ACCESSIBLE (R)
ACTION
ADD (R)
AFTER
AGAINST
AGGREGATE
ALGORITHM
ALL (R)
ALTER (R)
ANALYZE (R)
AND (R)
ANY
AS (R)
ASC (R)
ASCII
ASENSITIVE (R)
AT
AUTHORS
AUTOEXTEND_SIZE
AUTO_INCREMENT
AVG
AVG_ROW_LENGTH
B
BACKUP
BEFORE (R)
BEGIN
BETWEEN (R)
BIGINT (R)
BINARY (R)
BINLOG
BIT
BLOB (R)
BLOCK
BOOL
BOOLEAN
BOTH (R)
BTREE
BY (R)
BYTE
C
CACHE
CALL (R)
CASCADE (R)
CASCADED
CASE (R)
CATALOG_NAME
CHAIN
CHANGE (R)
CHANGED
CHAR (R)
CHARACTER (R)
CHARSET
CHECK (R)
CHECKSUM
CIPHER
CLASS_ORIGIN
CLIENT
CLOSE
COALESCE
CODE
COLLATE (R)
COLLATION
COLUMN (R)
COLUMNS
COLUMN_NAME
COMMENT
COMMIT
COMMITTED
COMPACT
COMPLETION
COMPRESSED
CONCURRENT
CONDITION (R)
CONNECTION
CONSISTENT
CONSTRAINT (R)
CONSTRAINT_CATALOG
CONSTRAINT_NAME
CONSTRAINT_SCHEMA
CONTAINS
CONTEXT
CONTINUE (R)
CONTRIBUTORS
CONVERT (R)
CPU
CREATE (R)
CROSS (R)
CUBE
CURRENT_DATE (R)
CURRENT_TIME (R)
CURRENT_TIMESTAMP (R)
CURRENT_USER (R)
CURSOR (R)
CURSOR_NAME
D
DATA
DATABASE (R)
DATABASES (R)
DATAFILE
DATE
DATETIME
DAY
DAY_HOUR (R)
DAY_MICROSECOND (R)
DAY_MINUTE (R)
DAY_SECOND (R)
DEALLOCATE
DEC (R)
DECIMAL (R)
DECLARE (R)
DEFAULT (R)
DEFINER
DELAYED (R)
DELAY_KEY_WRITE
DELETE (R)
DESC (R)
DESCRIBE (R)
DES_KEY_FILE
DETERMINISTIC (R)
DIRECTORY
DISABLE
DISCARD
DISK
DISTINCT (R)
DISTINCTROW (R)
DIV (R)
DO
DOUBLE (R)
DROP (R)
DUAL (R)
DUMPFILE
DUPLICATE
DYNAMIC
E
EACH (R)
ELSE (R)
ELSEIF (R)
ENABLE
ENCLOSED (R)
END
ENDS
ENGINE
ENGINES
ENUM
ERROR added in 5.5.3 (nonreserved)
ERRORS
ESCAPE
ESCAPED (R)
EVENT
EVENTS
EVERY
EXECUTE
EXISTS (R)
EXIT (R)
EXPANSION
EXPLAIN (R)
EXTENDED
EXTENT_SIZE
F
FALSE (R)
FAST
FAULTS
FETCH (R)
FIELDS
FILE
FIRST
FIXED
FLOAT (R)
FLOAT4 (R)
FLOAT8 (R)
FLUSH
FOR (R)
FORCE (R)
FOREIGN (R)
FOUND
FRAC_SECOND removed in 5.5.3
FROM (R)
FULL
FULLTEXT (R)
FUNCTION
G
GENERAL added in 5.5.3 (reserved); became nonreserved in 5.5.8
GEOMETRY
GEOMETRYCOLLECTION
GET_FORMAT
GLOBAL
GRANT (R)
GRANTS
GROUP (R)
H
HANDLER
HASH
HAVING (R)
HELP
HIGH_PRIORITY (R)
HOST
HOSTS
HOUR
HOUR_MICROSECOND (R)
HOUR_MINUTE (R)
HOUR_SECOND (R)
I
IDENTIFIED
IF (R)
IGNORE (R)
IGNORE_SERVER_IDS became nonreserved in 5.5.8
IMPORT
IN (R)
INDEX (R)
INDEXES
INFILE (R)
INITIAL_SIZE
INNER (R)
INNOBASE removed in 5.5.3
INNODB removed in 5.5.3
INOUT (R)
INSENSITIVE (R)
INSERT (R)
INSERT_METHOD
INSTALL
INT (R)
INT1 (R)
INT2 (R)
INT3 (R)
INT4 (R)
INT8 (R)
INTEGER (R)
INTERVAL (R)
INTO (R)
INVOKER
IO
IO_THREAD
IPC
IS (R)
ISOLATION
ISSUER
ITERATE (R)
J
JOIN (R)
K
KEY (R)
KEYS (R)
KEY_BLOCK_SIZE
KILL (R)
L
LANGUAGE
LAST
LEADING (R)
LEAVE (R)
LEAVES
LEFT (R)
LESS
LEVEL
LIKE (R)
LIMIT (R)
LINEAR (R)
LINES (R)
LINESTRING
LIST
LOAD (R)
LOCAL
LOCALTIME (R)
LOCALTIMESTAMP (R)
LOCK (R)
LOCKS
LOGFILE
LOGS
LONG (R)
LONGBLOB (R)
LONGTEXT (R)
LOOP (R)
LOW_PRIORITY (R)
M
MASTER
MASTER_CONNECT_RETRY
MASTER_HEARTBEAT_PERIOD became nonreserved in 5.5.8
MASTER_HOST
MASTER_LOG_FILE
MASTER_LOG_POS
MASTER_PASSWORD
MASTER_PORT
MASTER_SERVER_ID
MASTER_SSL
MASTER_SSL_CA
MASTER_SSL_CAPATH
MASTER_SSL_CERT
MASTER_SSL_CIPHER
MASTER_SSL_KEY
MASTER_SSL_VERIFY_SERVER_CERT (R)
MASTER_USER
MATCH (R)
MAXVALUE (R)
MAX_CONNECTIONS_PER_HOUR
MAX_QUERIES_PER_HOUR
MAX_ROWS
MAX_SIZE
MAX_UPDATES_PER_HOUR
MAX_USER_CONNECTIONS
MEDIUM
MEDIUMBLOB (R)
MEDIUMINT (R)
MEDIUMTEXT (R)
MEMORY
MERGE
MESSAGE_TEXT
MICROSECOND
MIDDLEINT (R)
MIGRATE
MINUTE
MINUTE_MICROSECOND (R)
MINUTE_SECOND (R)
MIN_ROWS
MOD (R)
MODE
MODIFIES (R)
MODIFY
MONTH
MULTILINESTRING
MULTIPOINT
MULTIPOLYGON
MUTEX
MYSQL_ERRNO
N
NAME
NAMES
NATIONAL
NATURAL (R)
NCHAR
NDB
NDBCLUSTER
NEW
NEXT
NO
NODEGROUP
NONE
NOT (R)
NO_WAIT
NO_WRITE_TO_BINLOG (R)
NULL (R)
NUMERIC (R)
NVARCHAR
O
OFFSET
OLD_PASSWORD
ON (R)
ONE
ONE_SHOT
OPEN
OPTIMIZE (R)
OPTION (R)
OPTIONALLY (R)
OPTIONS
OR (R)
ORDER (R)
OUT (R)
OUTER (R)
OUTFILE (R)
OWNER
P
PACK_KEYS
PAGE
PARSER
PARTIAL
PARTITION
PARTITIONING
PARTITIONS
PASSWORD
PHASE
PLUGIN
PLUGINS
POINT
POLYGON
PORT
PRECISION (R)
PREPARE
PRESERVE
PREV
PRIMARY (R)
PRIVILEGES
PROCEDURE (R)
PROCESSLIST
PROFILE
PROFILES
PROXY added in 5.5.7 (nonreserved)
PURGE (R)
Q
QUARTER
QUERY
QUICK
R
RANGE (R)
READ (R)
READS (R)
READ_ONLY
READ_WRITE (R)
REAL (R)
REBUILD
RECOVER
REDOFILE
REDO_BUFFER_SIZE
REDUNDANT
REFERENCES (R)
REGEXP (R)
RELAY added in 5.5.3 (nonreserved)
RELAYLOG
RELAY_LOG_FILE
RELAY_LOG_POS
RELAY_THREAD
RELEASE (R)
RELOAD
REMOVE
RENAME (R)
REORGANIZE
REPAIR
REPEAT (R)
REPEATABLE
REPLACE (R)
REPLICATION
REQUIRE (R)
RESET
RESIGNAL (R)
RESTORE
RESTRICT (R)
RESUME
RETURN (R)
RETURNS
REVOKE (R)
RIGHT (R)
RLIKE (R)
ROLLBACK
ROLLUP
ROUTINE
ROW
ROWS
ROW_FORMAT
RTREE
S
SAVEPOINT
SCHEDULE
SCHEMA (R)
SCHEMAS (R)
SCHEMA_NAME
SECOND
SECOND_MICROSECOND (R)
SECURITY
SELECT (R)
SENSITIVE (R)
SEPARATOR (R)
SERIAL
SERIALIZABLE
SERVER
SESSION
SET (R)
SHARE
SHOW (R)
SHUTDOWN
SIGNAL (R)
SIGNED
SIMPLE
SLAVE
SLOW added in 5.5.3 (reserved); became nonreserved in 5.5.8
SMALLINT (R)
SNAPSHOT
SOCKET
SOME
SONAME
SOUNDS
SOURCE
SPATIAL (R)
SPECIFIC (R)
SQL (R)
SQLEXCEPTION (R)
SQLSTATE (R)
SQLWARNING (R)
SQL_BIG_RESULT (R)
SQL_BUFFER_RESULT
SQL_CACHE
SQL_CALC_FOUND_ROWS (R)
SQL_NO_CACHE
SQL_SMALL_RESULT (R)
SQL_THREAD
SQL_TSI_DAY
SQL_TSI_FRAC_SECOND removed in 5.5.3
SQL_TSI_HOUR
SQL_TSI_MINUTE
SQL_TSI_MONTH
SQL_TSI_QUARTER
SQL_TSI_SECOND
SQL_TSI_WEEK
SQL_TSI_YEAR
SSL (R)
START
STARTING (R)
STARTS
STATUS
STOP
STORAGE
STRAIGHT_JOIN (R)
STRING
SUBCLASS_ORIGIN
SUBJECT
SUBPARTITION
SUBPARTITIONS
SUPER
SUSPEND
SWAPS
SWITCHES
T
TABLE (R)
TABLES
TABLESPACE
TABLE_CHECKSUM
TABLE_NAME
TEMPORARY
TEMPTABLE
TERMINATED (R)
TEXT
THAN
THEN (R)
TIME
TIMESTAMP
TIMESTAMPADD
TIMESTAMPDIFF
TINYBLOB (R)
TINYINT (R)
TINYTEXT (R)
TO (R)
TRAILING (R)
TRANSACTION
TRIGGER (R)
TRIGGERS
TRUE (R)
TRUNCATE
TYPE
TYPES
U
UNCOMMITTED
UNDEFINED
UNDO (R)
UNDOFILE
UNDO_BUFFER_SIZE
UNICODE
UNINSTALL
UNION (R)
UNIQUE (R)
UNKNOWN
UNLOCK (R)
UNSIGNED (R)
UNTIL
UPDATE (R)
UPGRADE
USAGE (R)
USE (R)
USER
USER_RESOURCES
USE_FRM
USING (R)
UTC_DATE (R)
UTC_TIME (R)
UTC_TIMESTAMP (R)
V
VALUE
VALUES (R)
VARBINARY (R)
VARCHAR (R)
VARCHARACTER (R)
VARIABLES
VARYING (R)
VIEW
W
WAIT
WARNINGS
WEEK
WHEN (R)
WHERE (R)
WHILE (R)
WITH (R)
WORK
WRAPPER
WRITE (R)
X
X509
XA
XML
XOR (R)
Y
YEAR
YEAR_MONTH (R)
Z
ZEROFILL (R)
MySQL 5.5 New Keywords and Reserved Words
The following list shows the keywords and reserved words that are added in MySQL 5.5, compared to MySQL 5.1. Reserved keywords are marked with (R).
C
CATALOG_NAME
CLASS_ORIGIN
COLUMN_NAME
CONSTRAINT_CATALOG
CONSTRAINT_NAME
CONSTRAINT_SCHEMA
CURSOR_NAME
E
ERROR
G
GENERAL
I
IGNORE_SERVER_IDS
M
MASTER_HEARTBEAT_PERIOD
MESSAGE_TEXT
MYSQL_ERRNO
P
PROXY
R
RELAY
RELAYLOG
RESIGNAL (R)
S
SCHEMA_NAME
SIGNAL (R)
SLOW
SUBCLASS_ORIGIN
T
TABLE_NAME
X
XML
MySQL 5.5 Removed Keywords and Reserved Words
The following list shows the keywords and reserved words that are removed in MySQL 5.5, compared to MySQL 5.1. Reserved keywords are marked with (R).
FRAC_SECOND
INNOBASE
INNODB
SQL_TSI_FRAC_SECOND
原文:https://blog.csdn.net/u011479200/article/details/78664625