用于 CSV、TSV 和自定义分隔文件的 LazySimpleSerDe - Amazon Athena
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用于 CSV、TSV 和自定义分隔文件的 LazySimpleSerDe

此 SerDe 的指定是可选的。这是 Athena 在预设情况下使用的 CSV、TSV 和自定义分隔格式数据的 SerDe。如果不指定任何 SerDe,并且只指定 ROW FORMAT DELIMITED,则会使用此 SerDe。如果您的数据没有用引号引起来的值,请使用此 SerDe。

有关 LazySimpleSerDe 的参考文档,请参阅《Apache Hive 开发人员指南》中的 Hive SerDe 部分。

库名称

LazySimpleSerDe 的类库名称为 org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe。有关 LazySimpleSerDe 类的信息,请参阅 GitHub.com 上的 LazySimpleSerDe.java

忽略标题

要在您定义表时忽略标题,可以使用 skip.header.line.count 表属性,如下例所示。

TBLPROPERTIES ("skip.header.line.count"="1")

有关示例,请参阅 查询 Amazon VPC 流日志查询 Amazon CloudFront 日志 中的 CREATE TABLE 语句。

示例

以下示例显示如何使用 LazySimpleSerDe 根据 CSV 和 TSV 数据在 Athena 中创建表。要使用此 SerDe 反序列化自定义分隔的文件,请遵循示例中的模式,但使用 FIELDS TERMINATED BY 子句指定单字符分隔符。LazySimpleSerDe 不支持多字符分隔符。

注意

飞行表数据来自由美国运输部交通统计局提供的航班。从原来的数据中进行稀释。

CSV 示例

使用 CREATE TABLE 语句根据在 Amazon S3 中存储的底层 CSV 数据创建一个 Athena 表。

CREATE EXTERNAL TABLE flight_delays_csv ( yr INT, quarter INT, month INT, dayofmonth INT, dayofweek INT, flightdate STRING, uniquecarrier STRING, airlineid INT, carrier STRING, tailnum STRING, flightnum STRING, originairportid INT, originairportseqid INT, origincitymarketid INT, origin STRING, origincityname STRING, originstate STRING, originstatefips STRING, originstatename STRING, originwac INT, destairportid INT, destairportseqid INT, destcitymarketid INT, dest STRING, destcityname STRING, deststate STRING, deststatefips STRING, deststatename STRING, destwac INT, crsdeptime STRING, deptime STRING, depdelay INT, depdelayminutes INT, depdel15 INT, departuredelaygroups INT, deptimeblk STRING, taxiout INT, wheelsoff STRING, wheelson STRING, taxiin INT, crsarrtime INT, arrtime STRING, arrdelay INT, arrdelayminutes INT, arrdel15 INT, arrivaldelaygroups INT, arrtimeblk STRING, cancelled INT, cancellationcode STRING, diverted INT, crselapsedtime INT, actualelapsedtime INT, airtime INT, flights INT, distance INT, distancegroup INT, carrierdelay INT, weatherdelay INT, nasdelay INT, securitydelay INT, lateaircraftdelay INT, firstdeptime STRING, totaladdgtime INT, longestaddgtime INT, divairportlandings INT, divreacheddest INT, divactualelapsedtime INT, divarrdelay INT, divdistance INT, div1airport STRING, div1airportid INT, div1airportseqid INT, div1wheelson STRING, div1totalgtime INT, div1longestgtime INT, div1wheelsoff STRING, div1tailnum STRING, div2airport STRING, div2airportid INT, div2airportseqid INT, div2wheelson STRING, div2totalgtime INT, div2longestgtime INT, div2wheelsoff STRING, div2tailnum STRING, div3airport STRING, div3airportid INT, div3airportseqid INT, div3wheelson STRING, div3totalgtime INT, div3longestgtime INT, div3wheelsoff STRING, div3tailnum STRING, div4airport STRING, div4airportid INT, div4airportseqid INT, div4wheelson STRING, div4totalgtime INT, div4longestgtime INT, div4wheelsoff STRING, div4tailnum STRING, div5airport STRING, div5airportid INT, div5airportseqid INT, div5wheelson STRING, div5totalgtime INT, div5longestgtime INT, div5wheelsoff STRING, div5tailnum STRING ) PARTITIONED BY (year STRING) ROW FORMAT DELIMITED FIELDS TERMINATED BY ',' ESCAPED BY '\\' LINES TERMINATED BY '\n' LOCATION 's3://athena-examples-myregion/flight/csv/';

每次将新分区添加到此表时,请运行 MSCK REPAIR TABLE 以刷新分区元数据:

MSCK REPAIR TABLE flight_delays_csv;

查询前 10 个延迟超过 1 小时的路线:

SELECT origin, dest, count(*) as delays FROM flight_delays_csv WHERE depdelayminutes > 60 GROUP BY origin, dest ORDER BY 3 DESC LIMIT 10;

TSV 示例

使用 CREATE TABLE 语句根据在 Amazon S3 中存储的 TSV 数据创建一个 Athena 表。使用 ROW FORMAT DELIMITED 并指定制表符字段分隔符、行分隔符和转义字符,如下所示:

... ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t' ESCAPED BY '\\' LINES TERMINATED BY '\n' ...

以下示例 CREATE TABLE 语句。

CREATE EXTERNAL TABLE flight_delays_tsv ( yr INT, quarter INT, month INT, dayofmonth INT, dayofweek INT, flightdate STRING, uniquecarrier STRING, airlineid INT, carrier STRING, tailnum STRING, flightnum STRING, originairportid INT, originairportseqid INT, origincitymarketid INT, origin STRING, origincityname STRING, originstate STRING, originstatefips STRING, originstatename STRING, originwac INT, destairportid INT, destairportseqid INT, destcitymarketid INT, dest STRING, destcityname STRING, deststate STRING, deststatefips STRING, deststatename STRING, destwac INT, crsdeptime STRING, deptime STRING, depdelay INT, depdelayminutes INT, depdel15 INT, departuredelaygroups INT, deptimeblk STRING, taxiout INT, wheelsoff STRING, wheelson STRING, taxiin INT, crsarrtime INT, arrtime STRING, arrdelay INT, arrdelayminutes INT, arrdel15 INT, arrivaldelaygroups INT, arrtimeblk STRING, cancelled INT, cancellationcode STRING, diverted INT, crselapsedtime INT, actualelapsedtime INT, airtime INT, flights INT, distance INT, distancegroup INT, carrierdelay INT, weatherdelay INT, nasdelay INT, securitydelay INT, lateaircraftdelay INT, firstdeptime STRING, totaladdgtime INT, longestaddgtime INT, divairportlandings INT, divreacheddest INT, divactualelapsedtime INT, divarrdelay INT, divdistance INT, div1airport STRING, div1airportid INT, div1airportseqid INT, div1wheelson STRING, div1totalgtime INT, div1longestgtime INT, div1wheelsoff STRING, div1tailnum STRING, div2airport STRING, div2airportid INT, div2airportseqid INT, div2wheelson STRING, div2totalgtime INT, div2longestgtime INT, div2wheelsoff STRING, div2tailnum STRING, div3airport STRING, div3airportid INT, div3airportseqid INT, div3wheelson STRING, div3totalgtime INT, div3longestgtime INT, div3wheelsoff STRING, div3tailnum STRING, div4airport STRING, div4airportid INT, div4airportseqid INT, div4wheelson STRING, div4totalgtime INT, div4longestgtime INT, div4wheelsoff STRING, div4tailnum STRING, div5airport STRING, div5airportid INT, div5airportseqid INT, div5wheelson STRING, div5totalgtime INT, div5longestgtime INT, div5wheelsoff STRING, div5tailnum STRING ) PARTITIONED BY (year STRING) ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t' ESCAPED BY '\\' LINES TERMINATED BY '\n' LOCATION 's3://athena-examples-myregion/flight/tsv/';

每次将新分区添加到此表时,请运行 MSCK REPAIR TABLE 以刷新分区元数据:

MSCK REPAIR TABLE flight_delays_tsv;

查询前 10 个延迟超过 1 小时的路线:

SELECT origin, dest, count(*) as delays FROM flight_delays_tsv WHERE depdelayminutes > 60 GROUP BY origin, dest ORDER BY 3 DESC LIMIT 10;
注意

飞行表数据来自由美国运输部交通统计局提供的航班。从原来的数据中进行稀释。