What was the altitude of the yield of 1.4 megatons?
CREATE TABLE table_148578_1 (altitude__km_ VARCHAR, yield__approximate_ VARCHAR)
SELECT altitude__km_ FROM table_148578_1 WHERE yield__approximate_ = "1.4 megatons"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_148578_1 (altitude__km_ VARCHAR, yield__approximate_ VARCHAR) Question: What was the altitude of the yield of 1.4 megatons? [/INST] SELECT altitude__km_ FROM table_148578_1 WHERE yield__approximate_ = "1.4 megatons" </s>