Entity Framework Core PostgreSQL json query - postgresql

Question

Always return empty results
var collection = await _context.Settings
.Select(s => new
{
s.SettingId,
s.SettingParentId,
SettingValue = s.SettingValue.GetProperty(lang)
})
.Where(s => EF.Functions.JsonExists(s.SettingValue, lang))
.ToListAsync();
I try return only key from json but always return empty, when remove "select" works fine but i need only one key
This is the model
public class Setting
{
public string SettingId { get; set; }
public string SettingParentId { get; set; }
public JsonElement SettingValue { get; set; }
}

Answer 1

I think you're looking for something like the following:
class Program
{
static async Task Main(string[] args)
{
await using var ctx = new BlogContext();
await ctx.Database.EnsureDeletedAsync();
await ctx.Database.EnsureCreatedAsync();
var lang = "es";
var collection = await ctx.Settings
.Where(s => EF.Functions.JsonExists(s.SettingValue, lang))
.Select(s => new
{
s.SettingId,
s.SettingParentId,
SettingValue = s.SettingValue.GetProperty(lang).GetString()
})
.ToListAsync();
foreach (var i in collection)
{
Console.WriteLine($"{i.SettingId}: {i.SettingValue}");
}
}
}
public class BlogContext : DbContext
{
public DbSet<Setting> Settings { get; set; }
static ILoggerFactory ContextLoggerFactory
=> LoggerFactory.Create(b => b.AddConsole().AddFilter("", LogLevel.Information));
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
=> optionsBuilder
.UseNpgsql(#"Host=localhost;Username=test;Password=test")
.EnableSensitiveDataLogging()
.UseLoggerFactory(ContextLoggerFactory);
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<Setting>().HasData(new Setting
{
SettingId = "1",
SettingValue = JsonDocument.Parse(#"{ ""es"" : ""valor""}").RootElement
});
}
}
public class Setting
{
public string SettingId { get; set; }
public string SettingParentId { get; set; }
public JsonElement SettingValue { get; set; }
}