Translating natural language requests into robust, production-ready data transformations remains a challenging task. Accuracy relies on precise schema mapping and warehouse-specific SQL dialects, and the strongest supervision available during training (execution success and result matching) is provided only at the sequence level. At the same time, assembling large, execution-validated corpora is costly, and token-level objectives do not align with these global signals, resulting in unstable optimization and limited portability. Thinkquel is a fine-tuned model for generating robust, portable, and execution-validated database queries. Thinkquel's methodology incorporates TS-SQL, a novel synthetic data pipeline that leverages dbt as a portable intermediate representation, and TS-GRPO (Token-Sequence GRPO), a span-aware reinforcement learning objective specifically designed to bridge the gap between token-level training signals and sequence-level execution rewards when fine-tuning LLM. On the 500-example TS-SQL test set, Thinkquel (32B) achieved a 93.2% execution success rate and 61.8% accurate match rate with a two-stage SFT curriculum, improving the baseline model by 67.2% (execution) and 44.4% (match). In Spider (14B) experiments, TS-GRPO improved training stability and convergence speed compared to GRPO and GSPO.