交融查问语法

etl-engine引擎中的交融查问提供将多源数据在内存中重组关联查问并输入查问后果的能力。
交融查问语法遵循ANSI SQL规范，与惯例MySQL查问语法很类似。

  • 反对对多种类别数据库之间读取的数据进行交融查问。
  • 反对音讯流数据传输过程中动静产生的数据与多种类型数据库之间的流计算查问。
  • 交融查问语法遵循ANSI SQL规范。

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

语法格局

  • select 反对
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 反对
    INNER JOIN、LEFT JOIN、RIGHT JOIN、OUTER JOIN、CROSS JOIN等

运算符反对

+ - * / == < <= > >= <> != || IS BETWEEN IN LIKE NOT ANY AND OR INTERSECT UNION EXCEPT EXISTS

函数反对

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)