多列IN/ANY postgres查询

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英文:

Multi-column IN/ANY postgres query

问题

示例表模式:

create table t1(
  col1 varchar(20),
  col2 varchar(20)
);

要求:
获取与数组中提供的任何元组(col1,col2)匹配的行。

SQL:

select * from t1 where (col1, col2) in (('c11', 'c12'), ('c21', 'c22'));

我想使用“database/sql”包和“github.com/lib/pq”驱动程序在Go中编写此查询,这就是我遇到问题的地方。

对于单列IN/ANY查询,我可以很容易地实现。

例如,以下查询

select * from t1 where col1 in ('c11', 'c21');

可以使用以下代码片段实现:

args := []string{"c11", "c21"}
conn.Exec(`select * from t1 where col1 = any($1)`, pq.Array(args))

然而,我无法对多列查询使用类似的方法。
我尝试将pq.Array([][]string)pq.Array([]*pq.StringArray)等作为参数传递,但它们不起作用,并返回以下错误:

input of anonymous composite types is not implemented

对此将不胜感激。

英文:

Sample table schema:

create table t1(
  col1 varchar(20),
  col2 varchar(20)
);

Requirement:
Fetch rows that match any of the tuples (col1, col2) presented in an array.

SQL:

select * from t1 where (col1, col2) in (('c11', 'c12'), ('c21', 'c22'));

I want to write this query in Go using the "database/sql" package with "github.com/lib/pq" driver, and that is where I am facing the problem.

I can easily do this for single column IN/ANY query.

for example, the following query

select * from t1 where col1 in ('c11', 'c21');

can be achieved with the following code snippet:

args := []string{"c11", "c21}
conn.Exec(`select * from t1 where col1 = any($1)`, pq.Array(args))

However, I could not use similar approach for multi-column query.
I tried passing pq.Array([][]string), pq.Array([]*pq.StringArray) etc. as argument, but they do not work, and fetches the following error:

input of anonymous composite types is not implemented

Will appreciate any help on this.

答案1

得分: 1

你可以这样做:

args := [][]string{{"c11","c21"},{"c21","c22"}}
params := make([]interface{}, len(args)*2)
tuples := make([]string, len(args))
for i := range args {
    params[i*2] = args[i][0]
    params[i*2+1] = args[i][1]
    tuples[i] = fmt.Sprintf("($%d,$%d)", i*2+1,i*2+2)
}
invals := "(" + strings.Join(tuples, ",") + ")"
conn.Exec("SELECT * FROM t1 WHERE (col1,col2) IN " + invals, params...)

对于一个两列的元组,你可以这样做:

conn.Exec(`SELECT * FROM t1 WHERE (col1,col2) IN (
    SELECT * FROM json_each_text(json_object($1::text[]))
)`, pq.Array([][]string{{"c11","c21"},{"c21","c22"}}))
英文:

You could do the following:

args := [][]string{{"c11","c21"},{"c21","c22"}}
params := make([]interface{}, len(args)*2)
tuples := make([]string, len(args))
for i := range args {
    params[i*2] = args[i][0]
    params[i*2+1] = args[i][1]
    tuples[i] = fmt.Sprintf("($%d,$%d)", i*2+1,i*2+2)
}
invals := "(" + strings.Join(tuples, ",")) + ")"
conn.Exec("SELECT * FROM t1 WHERE (col1,col2) IN " + invals, params...)

For a two-column tuple you should be able to do the following:

conn.Exec(`SELECT * FROM t1 WHERE (col1,col2) IN (
    SELECT * FROM json_each_text(json_object($1::text[]))
)`, pq.Array([][]string{{"c11","c21"},{"c21","c22"}}))

huangapple
  • 本文由 发表于 2021年11月30日 16:36:44
  • 转载请务必保留本文链接:https://go.coder-hub.com/70166409.html
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