Question: **SQL query :** 

```
Select count(distinct signature)
from (Select table_name
      from information_schema.tables
      where table_schema="Log" and table_name like "%ERROR_%")
AS mytable;

```

**Expected output :** Number of distinct "Signature" from all tables.

**Actual output :** Unknown column 'signature' in 'field list';

Note : All my tables have signature a s a field name

Answer: 
What you want is for SymPy to update all the pertinent variables and give you the result: you want the equations you have defined *and* the values for a - d to be *simultaneously* true. The way to do this is give the values as additional simultaneous equations which must be true:

```
>>> solve((EqA,EqB,EqC,Eq(a,1),Eq(b,3),Eq(c,3),Eq(d,4)))
{c: 3, F_a: 4, a: 1, d: 4, F_b: 7, b: 3, T: 11}

```

And this shows your T=11 value that you were seeking.
How about:

```
results[T].subs({floorPickers: 15, modPickers: 35, periodOfInterest: 60*60, timePerPickMod: 1.0, timePerPickFloor: 1.0})

```