INSERT (OVERWRITE) INTO

INSERT OVERWRITE statement overwrites a table data of an existing table or a data in a given directory. Tajo’s INSERT OVERWRITE statement follows INSERT INTO SELECT statement of SQL. The examples are as follows:

create table t1 (col1 int8, col2 int4, col3 float8);

-- when a target table schema and output schema are equivalent to each other
INSERT OVERWRITE INTO t1 SELECT l_orderkey, l_partkey, l_quantity FROM lineitem;
-- or
INSERT OVERWRITE INTO t1 SELECT * FROM lineitem;

-- when the output schema are smaller than the target table schema
INSERT OVERWRITE INTO t1 SELECT l_orderkey FROM lineitem;

-- when you want to specify certain target columns
INSERT OVERWRITE INTO t1 (col1, col3) SELECT l_orderkey, l_quantity FROM lineitem;

In addition, INSERT OVERWRITE statement overwrites table data as well as a specific directory.

INSERT OVERWRITE INTO LOCATION '/dir/subdir' SELECT l_orderkey, l_quantity FROM lineitem;