Loading Table Column Types from Another Table

Hi Optrix ,

Have a look at this approach:

let
    // Type from text to actual
    // You will need that hardcoded
    TextTypes = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WKkmtKFHSUQoBUnohlQWpSrE60UqeeSWp6alFQHEgy8wEIeGWk59YkpmXrhCQn5kH0udXmpuUWgRVEAsA", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"json name" = _t, #"type" = _t]),
    TypeTable = Table.Distinct(Table.TransformColumns(TextTypes ,{{"type", (x) as type => Expression.Evaluate(x, #shared), type type}}), {"json name"}),

    // First table
    FirstTable = Table.FromRecords({
        [name = "George", age = 22, score=50],
        [name = "Sarah", age = 19, score=201]
    }),

    // Second Table
    SecondTable = Table.FromRecords({
        [name = "text", age = "Integer", score="Floating Point"]
    }),
    #"Add Types to Second Table" = Table.Join(Table.Transpose(Table.DemoteHeaders(SecondTable)), {"Column2"}, TypeTable, {"json name"}, JoinKind.Inner),
    TypeList = List.Zip ({#"Add Types to Second Table"[Column1], #"Add Types to Second Table"[type]}),

    // Transform Types
    #"Types to first table" = Table.TransformColumnTypes(FirstTable, TypeList)
in
    #"Types to first table" 

Edit:

Sorry, seems they've changed something in the engine since I've last used #shared, now they do not allow it at all.
For now, you can fall back to primitive types:

...
    TextTypes = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WKkmtKFHSUSqpLEhVALNjdaKVPPNKUtNTi2DieaW5SUAeSMYtJz+xJDMvXSEgPzOvBF1BLAA=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"json name" = _t, #"type" = _t]),
    TypeTable = Table.Distinct(Table.TransformColumns(TextTypes ,{{"type", (x) as type => Expression.Evaluate(x), type type}}), {"json name"}),
...

Hi, Optrix 

Please have this a try:

let
   FirstTable = Table.FromRecords({
        [name = "George", age = 22, score=50],
        [name = "Sarah", age = 19, score=201]
                                  }),
   SecondTable = Table.FromRecords({
        [name = "text", age = "Integer", score="Floating Point"]
                                  }),
                                  
   typeList = {{"Floating Point",Number.From},{"text", Text.From},{"Integer", Int64.From}},

   acc = List.Accumulate(
                         Table.ToColumns(Table.DemoteHeaders(SecondTable)),
                         FirstTable,
                         (x,y)=>
                               Table.TransformColumns(x,{y{0},List.Select(typeList,each _{0}=y{1}){0}{1}})
                        )
in
    acc

Hello Optrix 

check out this approach

let
   FirstTable = Table.FromRecords({
        [name = "George", age = 22, score=50],
        [name = "Sarah", age = 19, score=201]
    }),
   SecondTable = List.Zip({Table.ColumnNames(Table.FromRecords({
        [name = type text, age = Int64.Type, score=type number]
   })), Record.FieldValues(Table.First(Table.FromRecords({
        [name = type text, age = Int64.Type, score=type number]
   })))}),

Transform = Table.TransformColumnTypes
(
     FirstTable,
     SecondTable
)


in 
    Transform

Copy paste this code to the advanced editor in a new blank query to see how the solution works.

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Kudoes are nice too

Have fun

Jimmy