could not determine data type of parameter $1

I am trying to nest PG functions array_agg and json_build_object
I tried like this

select(({ fn, eb, val }) => {
      return fn
        .agg<
          {
            foo_col: string;
            bar_col:string;
          }[]
        >("array_agg", [
          eb.fn("json_build_object", [
            val("foo_col"),
            "sometable.foo",
            val("bar_col"),
            "sometable.bar",
            ]),
        ])
        .as("objs")

select(({ fn, eb, val }) => {
      return fn
        .agg<
          {
            foo_col: string;
            bar_col:string;
          }[]
        >("array_agg", [
          eb.fn("json_build_object", [
            val("foo_col"),
            "sometable.foo",
            val("bar_col"),
            "sometable.bar",
            ]),
        ])
        .as("objs")

However, i receive an error from Postgres

could not determine data type of parameter $1

could not determine data type of parameter $1

Looking at the compiled query,

val("foo_col")

val("foo_col")

seems to be replaced by

$1

$1

then applied as first param.
Why are val values parameterized since they are pretty much static ?
Why is postgres complaining about the type thing ?

Thank you.

Solution

Ok, perplexity gave me the answer.
You have to cast the key names à string with

cast(val("foo_col"), "text")

cast(val("foo_col"), "text")

Jump to solution

Kysely•13mo ago•

3 replies

Vjau

could not determine data type of parameter $1

I am trying to nest PG functions array_agg and json_build_object
I tried like this

select(({ fn, eb, val }) => {
      return fn
        .agg<
          {
            foo_col: string;
            bar_col:string;
          }[]
        >("array_agg", [
          eb.fn("json_build_object", [
            val("foo_col"),
            "sometable.foo",
            val("bar_col"),
            "sometable.bar",
            ]),
        ])
        .as("objs")

select(({ fn, eb, val }) => {
      return fn
        .agg<
          {
            foo_col: string;
            bar_col:string;
          }[]
        >("array_agg", [
          eb.fn("json_build_object", [
            val("foo_col"),
            "sometable.foo",
            val("bar_col"),
            "sometable.bar",
            ]),
        ])
        .as("objs")

However, i receive an error from Postgres

could not determine data type of parameter $1

could not determine data type of parameter $1

Looking at the compiled query,

val("foo_col")

val("foo_col")

seems to be replaced by

$1

$1

then applied as first param.
Why are val values parameterized since they are pretty much static ?
Why is postgres complaining about the type thing ?

Thank you.

Solution

Ok, perplexity gave me the answer.
You have to cast the key names à string with

cast(val("foo_col"), "text")

cast(val("foo_col"), "text")

Jump to solution

could not determine data type of parameter $1

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