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clickhouseCreate ReplacingMergeTree table


CREATE TABLE rt(id UInt32, ver UInt8, name String) ENGINE = ReplacingMergeTree(ver) ORDER BY idctrl + c
rt

name of the ReplacingMergeTree table to create

id UInt32

column to be used as a primary key

ver UInt8

version column (increment it to overwrite row identified by primary key)

name String

sample string column

(ver)

name of the version column

ORDER BY id

primary key (unique row identification) expression (id column in our case)


Usage example

CREATE TABLE rt(id UInt32, ver UInt8, name String) ENGINE = ReplacingMergeTree(ver) ORDER BY id;
INSERT INTO rt VALUES(1, 1, 'Donald');
INSERT INTO rt VALUES(1, 2, 'Joe');
SELECT * FROM rt FINAL;
output
┌─id─┬─ver─┬─name─┐
│  1 │   2 │ Joe  │
└────┴─────┴──────┘

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