融合查询语法
etl-engine引擎中的融合查询提供将多源数据在内存中重组关联查询并输出查询结果的能力。
融合查询语法遵循ANSI SQL标准，与常规MySQL查询语法很相似。
- 支持对多种类别数据库之间读取的数据进行融合查询。
- 支持消息流数据传输过程中动态产生的数据与多种类型数据库之间的流计算查询。
- 融合查询语法遵循ANSI SQL标准。
样本
SELECT
t_u.u_id,t_u.u_name,t_u.u_phone,
t_o.o_id,t_o.o_price,t_o.o_number,t_o.o_money,t_o.o_writetime,
t_p.p_id,t_p.p_name,t_p.p_contacts,t_p.p_desc
FROM t_u
inner JOIN t_o
ON t_o.u_id=t_u.u_id
inner JOIN t_p
ON t_o.p_id=t_p.p_id
ORDER BY
INTEGER(SUBSTRING(t_u.u_id,3)) ASC 语法格式
- select 支持
SELECT
[DISTINCT] field [, field ...]
FROM table [, table ...]
[WHERE condition]
[GROUP BY field [, field ...] ]
[HAVING condition]
[ORDER BY order_item [, order_item ...] ]
[LIMIT number_of_records [OFFSET number_of_records ] ]- table 支持
INNER JOIN、LEFT JOIN、RIGHT JOIN、OUTER JOIN、CROSS JOIN等
运算符支持
+ - * / == < <= > >= <> != || IS BETWEEN IN LIKE NOT ANY AND OR INTERSECT UNION EXCEPT EXISTS函数支持
逻辑函数
COALESCE(value [, value ...])
IF(condition, value1, value2)
IFNULL(value1, value2)
NULLIF(value1, value2)数字函数（30多个）
ABS(number)
ACOS(number)
ACOSH(number)
ASIN(number)
ASINH(number)
ATAN(number)
ATAN2(number2, number1)
ATANH(number)
CBRT(number)
CEIL(number)
COS(number)
COSH(number)
EXP(number)
EXP2(number)
EXPM1(number)
FLOOR(number)
IS_INF(number [, sign])
IS_NAN(number)
LOG(number)
LOG10(number)
LOG1P(number)
LOG2(number)
LOGB(number)
POW(base, exponent)
ROUND(number)
SIN(number)
SINH(number)
SQRT(number)
TAN(number)
TANH(number)
BIN_TO_DEC(bin)
OCT_TO_DEC(oct)
HEX_TO_DEC(hex)
ENOTATION_TO_DEC(enotation)
BIN(integer)
OCT(integer)
HEX(integer)
ENOTATION(float)
NUMBER_FORMAT(number [, precision, decimalPoint, thousandsSeparator, decimalSeparator])
RAND(min, max)日期函数（30多个）
NOW()
DATETIME_FORMAT(datetime, format)
YEAR(datetime)
MONTH(datetime)
DAY(datetime)
HOUR(datetime)
MINUTE(datetime)
SECOND(datetime)
MILLISECOND(datetime)
MICROSECOND(datetime)
NANOSECOND(datetime)
WEEKDAY(datetime)
UNIX_TIME(datetime)
UNIX_NANO_TIME(datetime)
DAY_OF_YEAR(datetime)
WEEK_OF_YEAR(datetime)
ADD_YEAR(datetime, duration)
ADD_MONTH(datetime, duration)
ADD_DAY(datetime, duration)
ADD_HOUR(datetime, duration)
ADD_MINUTE(datetime, duration)
ADD_SECOND(datetime, duration)
ADD_MILLI(datetime, duration)
ADD_MICRO(datetime, duration)
ADD_NANO(datetime, duration)
TRUNC_MONTH(datetime)
TRUNC_DAY(datetime)
TRUNC_TIME(datetime)
TRUNC_MINUTE(datetime)
TRUNC_SECOND(datetime)
TRUNC_MILLI(datetime)
TRUNC_MICRO(datetime)
TRUNC_NANO(datetime)
DATE_DIFF(datetime1, datetime2)
TIME_DIFF(datetime1, datetime2)
TIME_NANO_DIFF(datetime1, datetime2)
UTC(datetime)
MILLI_TO_DATETIME(unix_milliseconds)
NANO_TO_DATETIME(unix_nano_time)字符串函数（20多个）
TRIM(str)
LTRIM(str)
RTRIM(str)
UPPER(str)
LOWER(str)
BASE64_ENCODE(str)
BASE64_DECODE(str)
HEX_ENCODE(str)
HEX_DECODE(str)
LEN(str)
SUBSTRING(str, position [, len])
SUBSTR(str, position [, len])
INSTR(str, substr)
LIST_ELEM(str, sep, index)
REPLACE(str, old, new)
REGEXP_MATCH(str, regexp [, flags])
REGEXP_FIND(str, regexp [, flags])
TITLE_CASE(str)加密函数
MD5(str)
SHA1(str)
SHA256(str)
SHA512(str)
MD5_HMAC(str,key_str)
SHA1_HMAC(str,key_str)
SHA256_HMAC(str,key_str)
SHA512_HMAC(str,key_str) 类型转换函数
STRING(value)
INTEGER(value)
FLOAT(value)
DATETIME(value [, timezone])
BOOLEAN(value)聚合函数
COUNT([DISTINCT] *)
MIN(expr)
MAX(expr)
SUM([DISTINCT] expr)
AVG([DISTINCT] expr)参考资料
etl-engine使用手册(https://github.com/hw2499/etl-engine)
etl-crontab使用手册(https://github.com/hw2499/etl-engine/wiki/etl-crontab%E8%B0%83%E5%BA%A6)
嵌入脚本开发(https://github.com/hw2499/etl-engine/wiki/%E5%B5%8C%E5%85%A5%E8%84%9A%E6%9C%AC%E5%BC%80%E5%8F%91)
etl-engine配置样例(https://github.com/hw2499/etl-engine/wiki/etl-engine%E4%BD%BF%E7%94%A8%E6%A0%B7%E4%BE%8B)