What was the yield of the K-4 explosion?
CREATE TABLE table_148578_1 (yield__approximate_ VARCHAR, explosion VARCHAR)
SELECT yield__approximate_ FROM table_148578_1 WHERE explosion = "K-4"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_148578_1 (yield__approximate_ VARCHAR, explosion VARCHAR) Question: What was the yield of the K-4 explosion? [/INST] SELECT yield__approximate_ FROM table_148578_1 WHERE explosion = "K-4" </s>