This paper proposes the CRED-SQL framework to improve the accuracy of Text-to-SQL systems, which convert Natural Language Queries (NLQs) into SQL queries in large-scale databases. Existing Text-to-SQL systems suffer from poor accuracy due to schema matching errors and semantic drift caused by semantically similar attributes in large databases. CRED-SQL resolves this schema mismatch problem by accurately identifying tables and columns related to NLQs through cluster-based, large-scale schema search. Furthermore, by introducing Execution Description Language (EDL), an intermediate representation language between NLQ and SQL, CRED-SQL decomposes the task into two steps: Text-to-EDL and EDL-to-SQL. This decomposition leverages the powerful inference capabilities of LLMs while reducing semantic drift. Experimental results on two large-scale cross-domain benchmarks, SpiderUnion and BirdUnion, demonstrate CRED-SQL's effectiveness and scalability by achieving state-of-the-art performance.