如果不存在，则对 INSERT INTO 进行 Node-postgres 参数化查询

Question

我有一个用于插入语句的有效参数化查询，但我现在想添加一个 'WHERE NOT EXISTS' 子句。工作插入看起来像这样：

pgClient.query("INSERT INTO social_posts (username, user_image, message, image_url, post_id, post_url, location, network) VALUES (,,,,,,,)", postArray, 
    function(err, result) {...}

我想实现的是：

pgClient.query("INSERT INTO social_posts(username, user_image, message, image_url, post_id, post_url, location, network) SELECT (,,,,,,,) WHERE NOT EXISTS (SELECT 1 FROM social_posts WHERE post_id = )", postArray,
    function(err, result) {...}

在这种情况下，$9 实际上等于 postArray[4]。

我试过再次将值推入数组，但没有用：

error running query { [error: operator does not exist: character varying = bigint]
name: 'error',
length: 207,
severity: 'ERROR',
code: '42883',
detail: undefined,
hint: 'No operator matches the given name and argument type(s). You might need to add explicit type casts.',
position: '198',
internalPosition: undefined,
internalQuery: undefined,
where: undefined,
schema: undefined,
table: undefined,
column: undefined,
dataType: undefined,
constraint: undefined,
file: 'parse_oper.c',
line: '722',
routine: 'op_error' }

我尝试插入值，但没有用：

error running query { [error: there is no parameter ]
name: 'error',
length: 88,
severity: 'ERROR',
code: '42P02',
detail: undefined,
hint: undefined,
position: '114',
internalPosition: undefined,
internalQuery: undefined,
where: undefined,
schema: undefined,
table: undefined,
column: undefined,
dataType: undefined,
constraint: undefined,
file: 'parse_expr.c',
line: '823',
routine: 'transformParamRef' }

有人有什么想法吗？提前致谢！

Answer 1

经过一些研究，我发现了一些有用的东西 here。我无法让 $9 参数工作，因为它不能与插值一起工作的原因与 SELECT 项周围的一组额外括号有关。正确的语法是：

var postID = postArray[4].toString() // per joop's comment above

pgClient.query("INSERT INTO social_posts(username, user_image, message, image_url, post_id, post_url, location, network) SELECT ,,,,,,, WHERE NOT EXISTS (SELECT 1 FROM social_posts WHERE post_id = '" + postId + "')", postArray,
function(err, result) {...}

如果不存在，则对 INSERT INTO 进行 Node-postgres 参数化查询

Node-postgres parameterized query for INSERT INTO if not exists

postgresql

node.js

node-postgres