How do I add column name as a string to content of data

[rocuinneagain]

//Sample table

q)t:([] col1:("abc";"def");col2:("ghi";"jkl")) 
q)t col1 col2 ----------- "abc" "ghi" "def" "jkl" 
//qsql update 
update {"col1#",x} each col1,{"col2#",x} each col2 from t col1 col2 
--------------------- 
"col1#abc" "col2#ghi" "col1#def" "col2#jkl" 
//qsql improved using column name as variable 
update {string[x],"#",y}[`col1] each col1,{string[x],"#",y}[`col2] each col2 from t col1 col2 
--------------------- 
"col1#abc" "col2#ghi" "col1#def" "col2#jkl" \parse the query to see functional form 
parse"update {string[x],"#",y}[`col1] each col1,{string[x],"#",y}[`col2] each col2 from t" ! `t () 0b `col1`col2!((k){x'y};({string[x],"#",y};,`col1);`col1);(k){x'y};({string[x],"#",y};,`col2);`col2)) 
//Simplify functional form 
![t;();0b;{x!{(each;{string[x],(enlist "#"),y}[x];x)}each x}`col1`col2] col1 col2 
--------------------- 
"col1#abc" "col2#ghi" "col1#def" "col2#jkl"

[megan_mcp]

Hi ,

Can I just note that by converting your symbols to strings in col2, you are going to take up a lot more memory. If it isn’t essential they be stored in the table as strings, you could convert them while querying your data instead.

Of course this is only relevant if the table will be saved on disk and if you are interested in saving memory.

Thanks,

Megan