UPDATE CARBON TABLE
Function
This command is used to update the CarbonData table based on the column expression and optional filtering conditions.
Syntax
- Syntax 1:
UPDATE <CARBON TABLE> SET (column_name1, column_name2, ... column_name n) = (column1_expression , column2_expression , column3_expression ... column n_expression ) [ WHERE { <filter_condition> } ];
- Syntax 2:
UPDATE <CARBON TABLE> SET (column_name1, column_name2,) = (select sourceColumn1, sourceColumn2 from sourceTable [ WHERE { <filter_condition> } ] ) [ WHERE { <filter_condition> } ];
Parameter Description
Parameter |
Description |
---|---|
CARBON TABLE |
Name of the CarbonData table to be updated |
column_name |
Target column to be updated |
sourceColumn |
Column value of the source table that needs to be updated in the target table |
sourceTable |
Table from which the records are updated to the target table |
Precautions
Note the following before running this command:
- The UPDATE command fails if multiple input rows in the source table are matched with a single row in the target table.
- If the source table generates empty records, the UPDATE operation completes without updating the table.
- If rows in the source table do not match any existing rows in the target table, the UPDATE operation completes without updating the table.
- UPDATE is not allowed in the table with secondary index.
- In a subquery, if the source table and target table are the same, the UPDATE operation fails.
- The UPDATE operation fails if the subquery used in the UPDATE command contains an aggregate function or a GROUP BY clause.
For example, update t_carbn01 a set (a.item_type_code, a.profit) = ( select b.item_type_cd, sum(b.profit) from t_carbn01b b where item_type_cd =2 group by item_type_code);.
In the preceding example, aggregate function sum(b.profit) and GROUP BY clause are used in the subquery. As a result, the UPDATE operation will fail.
- If the carbon.input.segments property has been set for the queried table, the UPDATE operation fails. To solve this problem, run the following statement before the query:
Syntax:
SET carbon.input.segments. <database_name>. <table_name>=*;
Examples
- Example 1:
update carbonTable1 d set (d.column3,d.column5 ) = (select s.c33 ,s.c55 from sourceTable1 s where d.column1 = s.c11) where d.column1 = 'country' exists( select * from table3 o where o.c2 > 1);
- Example 2:
update carbonTable1 d set (c3) = (select s.c33 from sourceTable1 s where d.column1 = s.c11) where exists( select * from iud.other o where o.c2 > 1);
- Example 3:
update carbonTable1 set (c2, c5 ) = (c2 + 1, concat(c5 , "y" ));
- Example 4:
update carbonTable1 d set (c2, c5 ) = (c2 + 1, "xyx") where d.column1 = 'india';
- Example 5:
update carbonTable1 d set (c2, c5 ) = (c2 + 1, "xyx") where d.column1 = 'india' and exists( select * from table3 o where o.column2 > 1);
System Response
Success or failure will be recorded in the driver log and on the client.
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