What is the population in millions for 2011 where the GDP (nominal) (billions USD) is 4? 
CREATE TABLE table_2155836_1 (population__millions VARCHAR, _2011_ VARCHAR, gdp__nominal___billions_usd_ VARCHAR)
SELECT population__millions, _2011_ FROM table_2155836_1 WHERE gdp__nominal___billions_usd_ = "4"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_2155836_1 (population__millions VARCHAR, _2011_ VARCHAR, gdp__nominal___billions_usd_ VARCHAR) Question: What is the population in millions for 2011 where the GDP (nominal) (billions USD) is 4?  [/INST] SELECT population__millions, _2011_ FROM table_2155836_1 WHERE gdp__nominal___billions_usd_ = "4" </s>