[英]How to use left clause in doctrine?
this is my query for find all records in table and sort from the oldest. 这是我的查询,用于查找表中的所有记录并从最早的记录开始排序。 I want to limit one column to only 50 characters.
我想将一列限制为仅50个字符。 I can't find any information how to change this query for use left clause.
我找不到任何信息来更改此查询以使用left子句。
$posts = $ChocoPosts->findBy(array(), array('id' => 'DESC'));
Additionally i tried use clean sql syntax for that, but it's not show any records. 此外,我尝试为此使用干净的sql语法,但未显示任何记录。
$conn = $this->getDoctrine()->getManager()->getConnection();
$sql = '
SELECT id, title, left(content, 45), date_add, img
FROM choco_posts
ORDER BY id DESC
';
$stmt = $conn->prepare($sql);
$stmt->execute();
$stmt->fetchAll();
I'm using symfony4 ant twig template. 我正在使用symfony4蚂蚁树枝模板。 I display all records in twig for loop.
我将所有记录显示在树枝中以进行循环。
You can simply use SUBSTRING
statement, as example: 您可以简单地使用
SUBSTRING
语句,例如:
$sql = '
SELECT id, title, SUBSTRING(content, 1, 45), date_add, img
FROM choco_posts
ORDER BY id DESC
';
By itself there is little difference, however left can potentially utilize an index while substring cannot. 本身没有什么区别,但是left可以潜在地利用索引,而substring则不能。
Hope this help 希望这个帮助
You can: 您可以:
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