INSERT Statements

INSERT Statements #

INSERT TABLE #

Description #

The INSERT TABLE statement is used to insert rows into a table or overwrite the existing data in the table. The row to be inserted can be specified by value expressions or result from query.

Syntax # 

-- Stardard syntax
INSERT { OVERWRITE TABLE | INTO [TABLE] }  tablename
 [PARTITION (partcol1[=val1], partcol2[=val2] ...) [IF NOT EXISTS]]
   { VALUES ( value [, ..] ) [, ( ... ) ] | select_statement FROM from_statement }

Parameters #

  • OVERWRITE TABLE

    If specify OVERWRITE TABLE, it will overwrite any existing data in the table or partition.

  • PARTITION ( ... )

    An option to specify insert data into table’s specific partitions. If the PARTITION clause is specified, the table should be a partitioned table.

  • VALUES ( value [, ..] ) [, ( ... ) ]

    Specifies the values to be inserted explicitly. A comma must be used to separate each value in the clause. More than one set of values can be specified to insert multiple rows.

  • select_statement

    A statement for query. See more details in queries.

Synopsis #

Dynamic Partition Inserts #

When writing data into Hive table’s partition, users can specify the list of partition column names in the PARTITION clause with optional column values. If all the partition columns’ value are given, we call this a static partition, otherwise it is a dynamic partition.

Each dynamic partition column has a corresponding input column from the select statement. This means that the dynamic partition creation is determined by the value of the input column.

The dynamic partition columns must be specified last among the columns in the SELECT statement and in the same order in which they appear in the PARTITION() clause.

Note:

In Hive, by default, users must specify at least one static partition in case of accidentally overwriting all partitions, and users can set the configuration hive.exec.dynamic.partition.mode to nonstrict to allow all partitions to be dynamic.

But in Flink’s Hive dialect, it’ll always be nonstrict mode which means all partitions are allowed to be dynamic.

Examples # 

-- insert into table using values
INSERT INTO t1 VALUES ('k1', 'v1'), ('k2', 'v2');

-- insert overwrite
INSERT OVERWRITE TABLE t1 VALUES ('k1', 'v1'), ('k2', 'v2');;

-- insert into table using select statement
INSERT INTO TABLE t1 SELECT * FROM t2;

-- insert into  partition
--- static partition
INSERT INTO t1 PARTITION (year = 2022, month = 12) SELECT value FROM t2;

--- dynamic partition 
INSERT INTO t1 PARTITION (year = 2022, month) SELECT value, month FROM t2;
INSERT INTO t1 PARTITION (year, month) SELECT value, 2022, month FROM t2;

INSERT OVERWRITE DIRECTORY #

Description #

Query results can be inserted into filesystem directories by using a slight variation of the syntax above:

-- Standard syntax
INSERT OVERWRITE [LOCAL] DIRECTORY directory_path
  [ROW FORMAT row_format] [STORED AS file_format] 
  { VALUES ( value [, ..] ) [, ( ... ) ] | select_statement FROM from_statement }

row_format:
  : DELIMITED [FIELDS TERMINATED BY char [ESCAPED BY char]] [COLLECTION ITEMS TERMINATED BY char]
      [MAP KEYS TERMINATED BY char] [LINES TERMINATED BY char]
      [NULL DEFINED AS char]
  | SERDE serde_name [WITH SERDEPROPERTIES (property_name=property_value, ...)

Parameters #

  • directory_path

    The path for the directory to be inserted can be a full URI. If scheme or authority are not specified, it’ll use the scheme and authority from the Flink configuration variable fs.default-scheme that specifies the filesystem scheme.

  • LOCAL

    The LOCAL keyword is optional. If LOCAL keyword is used, Flink will write data to the directory on the local file system.

  • VALUES ( value [, ..] ) [, ( ... ) ] Specifies the values to be inserted explicitly. A comma must be used to separate each value in the clause. More than one set of values can be specified to insert multiple rows.

  • select_statement

    A statement for query. See more details in queries.

  • STORED AS file_format

    Specifies the file format to use for the insert. The data will be stored as specific file format. The valid value are TEXTFILE, ORC, PARQUET, AVRO, RCFILE, SEQUENCEFILE, JSONFILE. For more details, please refer to Hive’s doc Storage Formats.

  • row_format

    Specifies the row format for this insert. The data will be serialized to file with the specific property. For more details, please refer to Hive’s doc RowFormat.

Synopsis #

Examples # 

--- insert directory with specific format
INSERT OVERWRITE DIRECTORY '/user/hive/warehouse/t1' STORED AS ORC SELECT * FROM t1;

-- insert directory with specific row format
INSERT OVERWRITE LOCAL DIRECTORY '/tmp/t1'
  ROW FORMAT DELIMITED FIELDS TERMINATED BY ':'
  COLLECTION ITEMS TERMINATED BY '#'
  MAP KEYS TERMINATED BY '=' SELECT * FROM t1;

Multiple Inserts #

Hive dialect enables users to insert into multiple destinations in one single statement. Users can mix inserting into table and inserting into directory in one single statement. In such syntax, Flink will minimize the number of data scans requires. Flink can insert data into multiple tables/directories by scanning the input data just once.

Syntax # 

-- multiple insert into table
FROM from_statement
  INSERT { OVERWRITE TABLE | INTO [TABLE] } tablename1 [PARTITION (partcol1=val1, partcol2=val2 ...) [IF NOT EXISTS]] select_statement1,
  INSERT { OVERWRITE TABLE | INTO [TABLE] } tablename2 [PARTITION ... [IF NOT EXISTS]] select_statement2
  [, ... ]

-- multiple insert into directory
FROM from_statement
  INSERT OVERWRITE [LOCAL] DIRECTORY directory1_path [ROW FORMAT row_format] [STORED AS file_format] select_statement1,
  INSERT OVERWRITE [LOCAL] DIRECTORY directory2_path [ROW FORMAT row_format] [STORED AS file_format] select_statement2
  [, ... ]

row_format:
  : DELIMITED [FIELDS TERMINATED BY char [ESCAPED BY char]] [COLLECTION ITEMS TERMINATED BY char]
      [MAP KEYS TERMINATED BY char] [LINES TERMINATED BY char]
      [NULL DEFINED AS char]
  | SERDE serde_name [WITH SERDEPROPERTIES (property_name=property_value, ...)]

Examples # 

-- multiple insert into table
FROM (SELECT month, value from t1) t
  INSERT OVERWRITE TABLE t1_1 SELECT value WHERE month <= 6
  INSERT OVERWRITE TABLE t1_2 SELECT value WHERE month > 6;

-- multiple insert into directory
FROM (SELECT month, value from t1) t
  INSERT OVERWRITE DIRECTORY '/user/hive/warehouse/t1/month1' SELECT value WHERE month <= 6
  INSERT OVERWRITE DIRECTORY '/user/hive/warehouse/t1/month2' SELECT value WHERE month > 6;
    
-- mixed with insert into table/directory in one single statement
FROM (SELECT month, value from t1) t
  INSERT OVERWRITE TABLE t1_1 SELECT value WHERE month <= 6
  INSERT OVERWRITE DIRECTORY '/user/hive/warehouse/t1/month2' SELECT value WHERE month > 6;