How do return the count of a particular field in psql db - postgresql

Question

I have a database tables with the relationships as below.
Cagetory ---> CategorItems //One to many(CategoryItem has categoryId colum)
CatgeoryItems ---> Post // One to many(Post has categoryItemId).
I want to count the total number of records in Post groupBy the categoryItemId also returning along the categoryItem name, and the categoryName. I want columns like returned
CategoryName, item, totalInPostTable
I am using sequelize rdb mapper. When i use the query below
models.Post.findAll({
include: [{
model: models.CategoryItem,
attributes: ['item'],
required: true,
include: [{
model: models.Category,
attributes: ['name'],
required: true,
group: ["name"]
}]
}],
attributes: ['categoryItemId'],
})
It returns the record below
{
"categoryItemId": 1,
"CategoryItem": {
"item": "xxxxxx",
"Category": {
"name": "xxxxxx"
}
}
},
{
"categoryItemId": 1,
"CategoryItem": {
"item": "xxxxxx",
"Category": {
"name": "xxxxxx"
}
}
},
{
"categoryItemId": 1,
"CategoryItem": {
"item": "xxxxxx",
"Category": {
"name": "xxxxxx"
}
}
},
{
"categoryItemId": 1,
"CategoryItem": {
"item": "xxxxxx",
"Category": {
"name": "xxxxxx"
}
}
},
{
"categoryItemId": 1,
"CategoryItem": {
"item": "xxxxxx",
"Category": {
"name": "xxxxxx"
}
}
},
{
"categoryItemId": 2,
"CategoryItem": {
"item": "xxxxxx",
"Category": {
"name": "xxxxxx"
}
}
},
{
"categoryItemId": 4,
"CategoryItem": {
"item": "xxxxxx",
"Category": {
"name": "xxxxxx"
}
}
}
However,it failed and return null without error as soon as i groupBy the categpryItem id like below.
models.Post.findAll({
include: [{
model: models.CategoryItem,
attributes: ['item', [sequelize.fn('COUNT', sequelize.col('id')), 'no_category']],
required: true,
include: [{
model: models.Category,
attributes: ['name'],
required: true,
}]
}],
attributes: ['categoryItemId'],
group: ["categoryItemId"]
})
Pls what am i doing wrong ? ANy help would be appreciated.