Subscription in SQL Server using where on date field doesn't work

### Version Information

Server Version: 2.37.1

### Environment

OSS

### What is the current behaviour?

All subscriptions with a filter on a date field doesn't work on SQL Server 2019
```
subscription AAAA {
exampleTable(where: {dateField: {_eq: "2024-03-01"}}) {
id
}
}
```

This returns:

```
{
"data": null,
"errors": [
{
"message": "database query error",
"extensions": {
"path": "$",
"code": "unexpected"
}
}
]
}
```

### What is the expected behaviour?

I hoped it would work.

### How to reproduce the issue?

Using SQL Server 2019

1. Create a table with a date field
2. Do a subscription with a where condition in this date field
3. It should break instantly.
4. The same query should work using a query field.

### Please provide any traces or logs that could help here.

I've tracked down a little bit and I understand why this is happenning.

This is the generated query, by using the explain button on the console (i've manually renamed the table names from my own instance):

```
SELECT
[row].[result_id] AS [result_id],
[result].[json] AS [result]
FROM
OPENJSON(
CAST(
N'' + NCHAR(91) + '' + NCHAR(91) + '' + NCHAR(34) + '00000000-0000-0000-0000-000000000000' + NCHAR(34) + ',' + NCHAR(123) + '' + NCHAR(34) + 'cursor' + NCHAR(34) + '' + NCHAR(58) + '' + NCHAR(123) + '' + NCHAR(125) + ',' + NCHAR(34) + 'query' + NCHAR(34) + '' + NCHAR(58) + '' + NCHAR(123) + '' + NCHAR(125) + ',' + NCHAR(34) + 'session' + NCHAR(34) + '' + NCHAR(58) + '' + NCHAR(123) + '' + NCHAR(125) + ',' + NCHAR(34) + 'synthetic' + NCHAR(34) + '' + NCHAR(58) + '' + NCHAR(91) + '' + NCHAR(34) + '' + NCHAR(39) + '2024-03-01' + NCHAR(39) + '' + NCHAR(34) + '' + NCHAR(93) + '' + NCHAR(125) + '' + NCHAR(93) + '' + NCHAR(93) + '' AS NVARCHAR(MAX)
)
) WITH (
[result_id] uniqueidentifier '$[0]',
[result_vars] NVARCHAR(MAX) '$[1]' AS JSON
) AS [row]
OUTER APPLY (
SELECT
(
SELECT
ISNULL(
(
SELECT
[t_exampleTable1].[id] AS [id]
FROM
[dbo].[exampleTable] AS [t_exampleTable1]
WHERE
(
(
(
( [t_exampleTable1].[dateField]) = (
JSON_VALUE(
[row].[result_vars],
CAST(
N'' + NCHAR(36) + '.' + NCHAR(34) + 'synthetic' + NCHAR(34) + '' + NCHAR(91) + '0' + NCHAR(93) + '' AS NVARCHAR(MAX)
)
)
)
)
)
) FOR JSON PATH,
INCLUDE_NULL_VALUES
),
CAST(N'' + NCHAR(91) + '' + NCHAR(93) + '' AS NVARCHAR(MAX))
) AS [root]
) AS [exampleTable] FOR JSON PATH,
INCLUDE_NULL_VALUES,
WITHOUT_ARRAY_WRAPPER
) AS [result]([json]) FOR JSON PATH,
INCLUDE_NULL_VALUES
```

I've compared it with a query that uses a non-date field as filter

And the difference is this:

```
N'' + NCHAR(91) + '' + NCHAR(91) + '' + NCHAR(34) + '00000000-0000-0000-0000-000000000000' + NCHAR(34) + ',' + NCHAR(123) + '' + NCHAR(34) + 'cursor' + NCHAR(34) + '' + NCHAR(58) + '' + NCHAR(123) + '' + NCHAR(125) + ',' + NCHAR(34) + 'query' + NCHAR(34) + '' + NCHAR(58) + '' + NCHAR(123) + '' + NCHAR(125) + ',' + NCHAR(34) + 'session' + NCHAR(34) + '' + NCHAR(58) + '' + NCHAR(123) + '' + NCHAR(125) + ',' + NCHAR(34) + 'synthetic' + NCHAR(34) + '' + NCHAR(58) + '' + NCHAR(91) + '' + NCHAR(34) + '' + NCHAR(39) + '2024-03-01' + NCHAR(39) + '' + NCHAR(34) + '' + NCHAR(93) + '' + NCHAR(125) + '' + NCHAR(93) + '' + NCHAR(93) + '' AS NVARCHAR(MAX)
```
Which renders to:
```
[["00000000-0000-0000-0000-000000000000",{"cursor":{},"query":{},"session":{},"synthetic":["'2024-03-01'"]}]]
```

For comparaison, using another field in the filter I get this:
```
[["00000000-0000-0000-0000-000000000000",{"cursor":{},"query":{},"session":{},"synthetic":["10"]}]]
```

The only difference between the two of them is:
```
NCHAR(34) + '' + NCHAR(39) + '2024-03-01' + NCHAR(39) + '' + NCHAR(34)
```

```
NCHAR(34) + '10' + NCHAR(34)
```

So date fields here are getting single quotes while other fields don't.
The generated query starts working when I erase the two rogue NCHAR(39).
So I'm thinking the problem is some string parsing/filtering that is failing for dates and letting the single quotes there.

I have no idea if there's a setting in SQL Server that can make this work. I found it a little bit weird I'm the first one reporting this. I've tried with multiple tables and the same result.

In postgres this works properly.

### Any possible solutions/workarounds you're aware of?

I didn't found a workaround yet.

### Keywords

sql server mssql date subscription error

Start by reproducing the subscription with a date-field filter on SQL Server 2019 and compare its generated SQL with the equivalent query filter shown in the issue. Trace how the subscription's synthetic variables are serialized and consumed by the SQL Server query, then verify that the date filter works without the extra single quotes.

Written by the indexing model from the issue text.