Berakhot 44B

אמר רב יצחק בר אבדימי משום רבינו: על הביעא ועל מיני קופרא, בתחלה מברך ״שהכל״, ולבסוף ״בורא נפשות רבות וכו׳״. אבל ירקא לא. ורבי יצחק אמר: אפילו ירקא, אבל מיא ⁠— לא. ורב פפא אמר: אפילו מיא.

Rav Yitzḥak bar Avdimi said in the name of Rabbeinu, Rav: Over the egg and types of meat [kupra], at the start, one recites: By Whose word all things came to be, and at the end: Who creates the many forms of life. However, after eating vegetables, no, one does not recite a blessing at all. R' Yitzḥak said: Even after eating vegetables one recites a blessing; but after drinking water, no, one does not recite a blessing at all. And Rav Pappa said: Even after drinking water one must recite a blessing.

מר זוטרא עביד כרב יצחק בר אבדימי, ורב שימי בר אשי עביד כרבי יצחק. וסימנך: חד כתרי, ותרי כחד.

Mar Zutra acted in accordance with the opinion of R' Yitzḥak bar Avdimi and did not recite a blessing after eating vegetables, while Rav Shimi bar Ashi acted in accordance with the opinion of R' Yitzḥak and recited a blessing after eating vegetables. And a mnemonic by which to remember which Sage acted in accordance with which: One like two, and two like one. In other words, Mar Zutra, who is known only by his name and not by his patronymic, acted in accordance with Rav Yitzḥak bar Avdimi who is known by both his name and his patronymic. Rav Shimi bar Ashi, who is known by both his names, followed the opinion of R' Yitzḥak, who is known only by his first name.

אמר רב אשי: אנא, זמנא דכי מדכרנא, עבידנא ככולהו.

On this topic, Rav Ashi said: At times when I remember, I act in accordance with the opinions of all of them and recite a blessing even after drinking water.

תנן: כל שטעון ברכה לאחריו ⁠— טעון ברכה לפניו, ויש שטעון ברכה לפניו, ואין טעון ברכה לאחריו. בשלמא לרב יצחק בר אבדימי, לאפוקי ירקא. לרבי יצחק, לאפוקי מיא, אלא לרב פפא, לאפוקי מאי?

We learned in a Mishnah: Anything that requires a blessing after that requires a blessing beforehand; and there are items that require a blessing beforehand and do not require a blessing after that. If so, granted, according to Rav Yitzḥak bar Avdimi’s opinion, it excludes vegetables from the requirement to recite a blessing after that. And, granted, according to R' Yitzḥak’s opinion as well, it excludes water from the requirement to recite a blessing after that. However, according to Rav Pappa’s opinion, what does it exclude? What food requires a blessing before eating but does not require a blessing after eating?