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How to set timestamp of MySQL variable?

Failed to find out the reason why the variable @previousEndTimehas only a value YEAR.

Example data on my test pattern:

| id |   name |                     start |                       end |
|----|--------|---------------------------|---------------------------|
|  2 | test 1 | January, 01 2016 12:00:00 | January, 01 2016 13:00:00 |
|  3 | test 1 | January, 02 2016 11:00:00 | January, 02 2016 12:00:00 |
|  5 | test 1 | January, 03 2016 15:00:00 | January, 03 2016 16:00:00 |
|  6 | test 2 | January, 01 2016 10:00:00 | January, 01 2016 11:00:00 |
|  7 | test 2 | January, 02 2016 17:00:00 | January, 02 2016 18:00:00 |



SELECT
        id,
        name,
        @previousEndTime,
        @previousEndTime := end     
    FROM
        test_table, (SELECT @previousEndTime := 0) var
    ORDER BY name, id;

Current result:

| id |   name | @previousEndTime | @previousEndTime := end |
|----|--------|------------------|-------------------------|
|  2 | test 1 |                0 |     2016-01-01 13:00:00 |
|  3 | test 1 |             2016 |     2016-01-02 12:00:00 |
|  5 | test 1 |             2016 |     2016-01-03 16:00:00 |
|  6 | test 2 |             2016 |     2016-01-01 11:00:00 |
|  7 | test 2 |             2016 |     2016-01-02 18:00:00 |

Expected Result:

| id |   name |     @previousEndTime| @previousEndTime := end |
|----|--------|---------------------|-------------------------|
|  2 | test 1 |                0    |     2016-01-01 13:00:00 |
|  3 | test 1 |2016-01-01 13:00:00  |     2016-01-02 12:00:00 |
|  5 | test 1 |2016-01-02 12:00:00  |     2016-01-03 16:00:00 |
|  6 | test 2 |2016-01-03 16:00:00  |     2016-01-01 11:00:00 |
|  7 | test 2 |2016-01-01 11:00:00  |     2016-01-02 18:00:00 |

Please check FIDDLE

Note:

Other ways I've tried:

@previousEndTime := CONCAT('',end,'')

@previousEndTime := TIMESTAMP(CONCAT('',end,''))
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2 answers

Take a look at this;)

SQL Fiddle

MySQL 5.6 Schema :

DROP TABLE IF EXISTS `test_table`;
CREATE TABLE `test_table` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(50) CHARACTER SET utf8 NOT NULL,
  `start` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00' ON UPDATE CURRENT_TIMESTAMP,
  `end` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00' ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`)
);
INSERT INTO `test_table` VALUES ('2', 'test 1', '2016-01-01 12:00:00', '2016-01-01 13:00:00');
INSERT INTO `test_table` VALUES ('3', 'test 1', '2016-01-02 11:00:00', '2016-01-02 12:00:00');
INSERT INTO `test_table` VALUES ('5', 'test 1', '2016-01-03 15:00:00', '2016-01-03 16:00:00');
INSERT INTO `test_table` VALUES ('6', 'test 2', '2016-01-01 10:00:00', '2016-01-01 11:00:00');
INSERT INTO `test_table` VALUES ('7', 'test 2', '2016-01-02 17:00:00', '2016-01-02 18:00:00');

Request 1 :

SELECT
    id,
    name,
    if(@previousEndTime='0000-00-00 00:00:00',0,@previousEndTime),
    @previousEndTime := end     
FROM
    test_table,
    (
        SELECT
            @previousEndTime := '0000-00-00 00:00:00'
    ) var
ORDER BY name, id

Results :

| id |   name | if(@previousEndTime='0000-00-00 00:00:00',0,@previousEndTime) | @previousEndTime := end |
|----|--------|---------------------------------------------------------------|-------------------------|
|  2 | test 1 |                                                             0 |     2016-01-01 13:00:00 |
|  3 | test 1 |                                           2016-01-01 13:00:00 |     2016-01-02 12:00:00 |
|  5 | test 1 |                                           2016-01-02 12:00:00 |     2016-01-03 16:00:00 |
|  6 | test 2 |                                           2016-01-03 16:00:00 |     2016-01-01 11:00:00 |
|  7 | test 2 |                                           2016-01-01 11:00:00 |     2016-01-02 18:00:00 |
+2
source

try it,

    SELECT
        id,
        name,
        @previousEndTime,
        @previousEndTime := end     
    FROM
        test_table,
        (
            SELECT
                @previousEndTime := '0000-00-00 00:00:00'
        ) var
    ORDER BY name, id;

MySQL displays YEAR values ​​in YYYY format with a range from 1901 to 2155 or 0000.

1 2 "0" "99". MySQL 0 69 70 99 YEAR 2000 2069 1970 1999 .

0 0000 0000. 2000, "0" "00".

http://dev.mysql.com/doc/refman/5.7/en/year.html

+1

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